source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-1101 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
To avoid predators what is a good survival strategy? | [
"loud noises and movements",
"having brightly colored plumage",
"looking the same as leaves",
"resting in open spaces"
] | C | An example of camouflage is an organism looking like leaves |
OpenBookQA | OpenBookQA-1102 | thermal-radiation, thermal-conductivity
Title: How thermally conductive is a black body? Does a black body (imagine like a square of solid black-body-matter) thermally conduct well at room temperature? If you are talking of "black body" as in "black body radiation" better read the link:
A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.
"idealized" is the crucial point here. All matter can be approximated to a "black body", i.e an emitter of black body radiation by the multiplication with a constant specific for the material, the emissivity.
Thermal conductivity is a different concept than the attributes of a black body. It is measured experimentally and depends on the molecular structure.
A black body will have a specific modified black body spectrum of radiation but can have any type of conductivity.For example dull wrought iron and black concrete have the same emissivity , .94, but very different thermal conductivity.
The following is multiple choice question (with options) to answer.
Which object is likely to be a thermal conductor? | [
"curtain",
"wall",
"table",
"mirror"
] | D | metal is a thermal conductor |
OpenBookQA | OpenBookQA-1103 | everyday-life, aerodynamics, drag, turbulence
Title: Benefits of rear spoiler in cars What would be the benefits of rear spoilers in cars, like this one: From Wikipedia:
A spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion, usually described as turbulence or drag.
A rear spoiler is designed to change the flow of air over the rear of the vehicle. This change in air flow increases downforce on the rear of the vehicle to help improve traction in an effort to prevent sliding while cornering.
Benefit 1: Maintain Traction
Benefit 2: Increase Fuel Efficiency
Benefit 3: Create a Stylish Look
Benefit 4: Increase Braking Stability
The following is multiple choice question (with options) to answer.
As the wind is blowing on the back of a car with a strong gust, the car will | [
"rush forward faster than before",
"wind is unable to affect car speed",
"move forward instead of sideways",
"maintain speed and direction"
] | A | as force exerted on an object increases , distance travelled will increase |
OpenBookQA | OpenBookQA-1104 | orbit, earth, satellite, orbital-mechanics, artificial-satellite
There are a few details that may affect the answer: you should consider if the motion of the person will affect the answer to part (b) (and if not, why not). You should know that the Earth is not spherical. You should consider whether the optical refraction of light by the Earth's atmosphere should be considered. However, in a homework problem, such issues can often be ignored, as their effects are small.
The following is multiple choice question (with options) to answer.
The way that the earth rotates and moves through space can effect how | [
"the stars are viewed in the sky",
"how the moon phases",
"the heat of the sun",
"the plants we are able to eat"
] | A | stars appear to move relative to the horizon during the night |
OpenBookQA | OpenBookQA-1105 | I believe that the answer is 0.18.
geno3141 Jul 12, 2017
#2
+1129
+1
Geno, you have the hippo but you are missing the potamus.
(Using subscripted variables makes it easier to present and keep track of the relations.)
$$\small \text {Let A1 = {pass exam 1}, A2 = {pass exam 2}, A3 = {pass exam 3}, and A = {passes all three exams}. }\\$$
$$\text{Because }\ A^c_2\subset A^c, \; A^c_2\cap Ac=A^c_2 \\ \mathbb{P}(A^c_2) = \mathbb{P}(A^c_2|A^c_1)\; \cdot\; \mathbb{P}(A^c_1 +\mathbb{P}(A^c_2|A_1) \; \cdot\; \mathbb{P}(A_1) \leftarrow \small \text{Apply Total Probability Formula}\\ = (0 \cdot 0.1) + (0.2 \cdot 0.9) = 0.18 \\ \text {Then }\\ \mathbb{P}(A^c_2|A_c) = \dfrac {\mathbb{P}(A^c_2 \cap A^c)} {\mathbb{P}(A^c)}\\ = \dfrac {0.18}{0.496} = 0.363$$
GA
GingerAle Jul 12, 2017
edited by GingerAle Jul 12, 2017
#3
+1
Rhinoceros !!!!!!!
noun, plural rhinoceroses (especially collectively) rhinoceros.
1.
any of several large, thick-skinned, perissodactyl mammals of the family Rhinocerotidae, of Africa and India, having one or two upright horns on the snout: all rhinoceroses are endangered.
Guest Jul 12, 2017
#4
+92888
0
Thanks guest,
Yep, Ginger sure got that one wrong :)
Gino is definitely affiliated with rhinos, not hippos :))
The following is multiple choice question (with options) to answer.
The rhino population is smaller than before because | [
"cars crashed into rhinos",
"lions have become more effective at hunting rhinos",
"global warming has increased temperatures",
"people use parts for health remedies"
] | D | harming an animal species causes that animal 's population to decrease |
OpenBookQA | OpenBookQA-1106 | civil-engineering, hydrology
According to sources I've come across, flow through storm pipes
require an air gap so as to maintain open channel flow. Do I need to
maintain a specific amount of air gap? Or will any amount of air gap do?
Also, does it really matter whether or not I have an air gap? Do we
maintain an air gap so as to prevent a partial vacuum and self siphonage within the pipes? In which case why would it matter? Furthermore, since
storm sewer manholes (inlet pits) are open to the air, wouldn't that alleviate any pressure differentials? You're right, if your pipe is completely full then you don't have open channel flow. In other words, you can no longer use Manning's equation to model the flow in that pipe. You would have to use either Hazen-Williams or Darcy-Weisbach as you can no longer ignore the pressure term in Bernoulli's equation. As the depth of the water approaches full pipe depth, Manning's is going to become increasingly unreliable. So any air gap, while theoretically would relieve pressure, you can't rely on Manning's alone to model this. Furthermore, even if you model a pipe using pressure equations, models do not reflect the reality of how the pipe was installed anyways. So you shouldn't just say, yes I've provided 10 cm of air gap, therefore the pipe is not pressurized.
That being said, you don't have to ensure open channel flow in a pipe, you could design a system to function near full pipe for a 100-year storm. But as you mentioned in the second part of your question, any nearby manholes or inlets will surcharge and overflow, thus alleviating your pressure differentials (and flooding your site). If there is nothing to alleviate the pressure, the overflow can literally carry away manhole lids or blow them off in spectacular fashion in extreme cases.
Also consider that if your designed pipe is at capacity the amount of additional flow before you see flooding will be very small. Lastly, pressurized pipes are going to have additional stresses on them that will limit their durability.
The following is multiple choice question (with options) to answer.
If a person wants to decrease their risk of experiencing flooding | [
"they would live in a valley",
"they would live on a mountaintop",
"they would live in a flood plain",
"they would live below sea level"
] | B | as elevation of a place decreases , how much a flood will affect that place will increases |
OpenBookQA | OpenBookQA-1107 | fluid-dynamics, everyday-life, water
As can be seen from these photos, the colour dye is present in the water jets which recoil off the surface of the transparent pool water. However, not all of the water in the jets is from the coloured drop. Some of the original drop is trapped in a pocket below the surface, with the rebounding 'jets' having a 'coating' of the original drop material. The way we know this is because in the experiment, the coloured drop was made from water mixed with thymol blue, an indicator which is dark orange in colour at neutral-to-acidic pH. The pool water contained 0.1% sodium carbonate (alkali), which is transparent in colour, but when the two combined, the mixture turns blue in colour.
Some fascinating insight into the phenomenon can be gained by examining some high speed video footage.
If you look at this high speed video, you will see that when the water droplet falls into the water, it appears to bounce back out!
An even better example of the 'bouncing' phenonenon can be found in this video, when the drop is released gently from close to the surface of the water, it appears that after the drop is 'coalesced' into the water, part of it 'bounces' back out as a smaller droplet, which the falls back and floats on the surface of the water.
The explanation offered is that a layer of air gets trapped beneath the droplet as it hits the surface of the water. Some of the water in the droplet gets coalesced into the pool by the water tension, releasing a smaller droplet back out.
The following is multiple choice question (with options) to answer.
A splash in the pool caused the water to move | [
"in the nearby river",
"outside of the pool",
"in another nearby pool",
"on the other side of the pool"
] | D | dropping an object into water causes vibrations in the water |
OpenBookQA | OpenBookQA-1108 | thermodynamics, temperature, physical-chemistry, metrology
Title: How do you know mercury changes monotonically with temperature if mercury itself is used to make the thermometer? In the book I am reading recently "Concept of physics" volume 2 by professor H.C. Verma it says that (I am just summarizing the main points chronologically)
Energy is transferred from hot bodies to cold bodies when they are placed in contact.
The energy that transfer from one body to other without any mechanical work involved is called heat.
(then the book states zeroth law of thermodynamics)
All bodies in thermal equilibrium assigned equal temperature(I am assuming this definition of temperature).A hotter body is assigned higher temperature than a colder body.
Then the book says
Our next task is to define a scale temperature so that we can give numerical value to the temperature of a body. To do this we can choose a substance and look for its measurable quantity which monotonically changes with temperature.
The temperature can then be defined as a chosen function of this property.
The following is multiple choice question (with options) to answer.
when the mercury in a thermometer goes up, what does it indicate? | [
"there is a rise in heat",
"there is a rise in temperature",
"there is a rise in warmth",
"all of these"
] | D | temperature is a measure of heat energy |
OpenBookQA | OpenBookQA-1109 | Zz.
8. Jul 17, 2004
ohh, k , thanx
9. Jul 17, 2004
### BobG
Self Adjoint explained the math to it.
The reason behind it is this. Acceleration is fow fast your velocity is increasing. If you started out from rest and accelerated at 10 m/s^2, you would be travelling 10 m/s after one second. But you didn't travel 10 m/s for the entire second. You were travelling 0 m/s at time 0, 1 m/s after .1 seconds, 2 m/s after .2 seconds, etc. Your average velocity was 5 m/s (1/2 your acceleration).
This continues on even after the first second, except now you're starting at 10 m/s and reach 20 m/s by the end of the 2nd second. In other words, your average velocity for the 2nd second is 15 m/s. You total distance, so far, is 20 meters (5 meters the first second and 15 meters the 2nd second). You can keep going on second by second like this. The 1/2 a accounts for the non-constant velocity while the t^2 accounts for the accumulating distance from second to second.
10. Jul 17, 2004
### Entropy
Yeah back when I was a freshmen and just started physics I wondered what was up with that equation. Since I learned a little calculus I understand.
11. Jul 18, 2004
### JohnDubYa
I vote BobG has having the best answer.
12. Jul 19, 2004
### ArmoSkater87
its good, but i like gerben's better
13. Jul 19, 2004
### robphy
The following is multiple choice question (with options) to answer.
speed is a measure of how fast all these move but | [
"a person waiting",
"a fish swimming",
"a dog running",
"a bird flying"
] | A | speed is a measure of how fast an object is moving |
OpenBookQA | OpenBookQA-1110 | orbit, equinox, solstice
037, "Feb-07", 318.43
038, "Feb-08", 319.44
039, "Feb-09", 320.45
040, "Feb-10", 321.47
041, "Feb-11", 322.48
042, "Feb-12", 323.49
043, "Feb-13", 324.50
044, "Feb-14", 325.51
045, "Feb-15", 326.52
046, "Feb-16", 327.53
047, "Feb-17", 328.54
048, "Feb-18", 329.55
049, "Feb-19", 330.56
050, "Feb-20", 331.57
051, "Feb-21", 332.58
052, "Feb-22", 333.58
053, "Feb-23", 334.59
054, "Feb-24", 335.60
055, "Feb-25", 336.60
056, "Feb-26", 337.61
057, "Feb-27", 338.61
058, "Feb-28", 339.62
059, "Mar-01", 340.62
060, "Mar-02", 341.63
061, "Mar-03", 342.63
062, "Mar-04", 343.63
063, "Mar-05", 344.63
064, "Mar-06", 345.64
065, "Mar-07", 346.64
066, "Mar-08", 347.64
067, "Mar-09", 348.64
068, "Mar-10", 349.64
069, "Mar-11", 350.64
070, "Mar-12", 351.64
071, "Mar-13", 352.63
072, "Mar-14", 353.63
073, "Mar-15", 354.63
074, "Mar-16", 355.62
075, "Mar-17", 356.62
076, "Mar-18", 357.62
077, "Mar-19", 358.61
The following is multiple choice question (with options) to answer.
How many times does an equinox occur in the first half of the year | [
"three times",
"once",
"twice",
"four times"
] | B | an equinox occurs twice per year |
OpenBookQA | OpenBookQA-1111 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
A group of bunnies move into a field and start to have litters of kits, and soon rabbits are all over the field, so the foxes that live six miles away | [
"relocate to the field",
"eat all the bunnies",
"find new food sources",
"start to go hungry"
] | A | most predators live near the same environment as their prey |
OpenBookQA | OpenBookQA-1112 | algorithms
Title: In the Gas-Up problem, how is the amount of gas the same up to a cyclic shift regardless of starting city? I'm working through Elements of Programming Interviews as practice for finding a job. I've spent a ridiculous amount of time on Problem 18.7.
In the gas-up problem, $n$ cities are arranged on a circular road. You
need to visit all of the $n$ cities and come back to the starting
city. A certain amount of gas is available at each city. The total
amount of gas is equal to the amount of gas required to go around the
road once. Your gas tank has unlimited capacity. Call a city $c$
ample if you can begin at $c$ with an empty tank, refill at it, then travel through each of the remaining cities, refilling at each, and
return to $c$, without running out of gas at any point. See Figure
18.3 for an example. [You can see Figure 18.3 on the Google Books result if you search for "Elements of Programming Interviews Problem
18.7.]
Given an instance of the gas-up problem, how would you efficiently [i.e. in $\mathcal{O}(n)$ time or better]
compute an ample city, if one exists?
I couldn't figure it out. I read the hint, and I still couldn't figure it out. I gave up, and read the answer in the back of the book. I still couldn't figure it out. I searched Google and this site for a more complete solution, but didn't find one.
This is the part that's getting me:
On closer inspection, it becomes apparent that the graph of the amount
of gas as we perform the traversal is the same up to a cyclic shift
regardless of the starting city.
The following is multiple choice question (with options) to answer.
A man is filling up his tank at the gas station, then goes inside and pays. When he comes back out, his truck is being stolen! He chases the truck as the thief pulls away in it and begins to speed off. Though the truck was huge, right in front of him a moment ago, as the truck accelerates and the man struggles to keep up, the truck | [
"looks smaller",
"looks bigger",
"looks cold",
"looks away"
] | A | as distance to an object increases , that object will appear smaller |
OpenBookQA | OpenBookQA-1113 | material-science, everyday-life
Title: Paper stiffness As piece of paper is folded and unfolded, the stiffness of the sheet may seem to be greatly increased.
To those of you who don't recognise it: take a sheet of A4 paper, grasp one of the edges and move your hand vertically. Now fold the paper in half, unfold it and repeat.
Is anyone aware of any formal or heuristic explanation of what changed? You have stiffened the paper by greatly increasing its bending moment of intertia. This can occur in at least two ways:
1.) When you unfolded the paper, it still had some residual bend which made the paper form a very shallow 'V'. Even though shallow. it is much deeper than the thickness of the original paper.
2.) When you unfolded the paper, it still had some residual bend which made the paper form a very shallow 'V' which was very localized to the area next to the bend. Even if you refold the paper in the opposite way, to take out or minimize the original fold, there is still a shallow 'V'. Even though it might be much shallower than in case 1, it is much deeper than the thickness of the original paper.
In both cases, the increased resistance to bending comes from the new geometry of the paper, more specifially, the geometry of a cross-section of the paper which goes through the bend.
Think of the unbent paper as a beam. Its resistance to bending is proportional to b(d^3), where 'b' is the width of the beam and 'd' is the depth. If you take a piece of 8.5" x 11" piece of paper and lay it flat over a pencil on the table, the paper will flop so that both ends touch the table. The paper forms a beam: 'b' is 8.5" or 11" (depending on how you laid the paper) and 'd' is the thickness of the sheet (say, about one one-hundreth of an inch).
How to improve the stiffness and strength of this beam? Fold the paper, accordion-style, with sharp 1/2" folds. Then lay it across the pencil, so that the folds are perdendicular to the pencil.
The following is multiple choice question (with options) to answer.
A piece of paper is a different shape when it | [
"is made into a paper fan",
"is on a desk",
"has a drawing on it",
"has words on it"
] | A | folding an object causes that object to change shape |
OpenBookQA | OpenBookQA-1114 | botany
Title: Greyish spots behind a peach's stone, what could they be? I'm sorry if it's a silly question, but what are those greyish spots behind the stone of this peach (or whatever this is)? What are they for? Are they safe to eat? The fruit is ok from the outside Callus can develop inside peaches (https://www.tasteofhome.com/article/peach-callus-tissue/), between the mesocarp and the endocarp. Callus is edible and harmless. It's a tissue composed of unorganised parenchyma cells, which in turn are multi-purpose cells that can be found in a number of "soft" tissues with metabolic purposes including, but not limited to, the mesocarp and the endosperm. Callus' main purpose is to seal damaged tissues, see for instance:
this blogpost that explains the difference between mold and callus in a peach where there actually is a mold infection (which you should not eat)
its counterpart where there is no mold, but a considerable amount of callus (way more than you have there) was produced because the stone had split open; this one would be safe to eat, once you've ascertained that there is no mold, although callus may contain pieces of hard tissue from the stone.
Small quantities of callus can appear as leftovers form older and smaller lesions.
The following is multiple choice question (with options) to answer.
There are some decorative fruits used for holidays where the outside is carved, such as large orange ones. The insides of these fruits, similar to gourds, most commonly | [
"may have moisture removed and inside parts are devoured",
"may be burned and thrown away",
"may be mixed with sand",
"may be used in concrete"
] | A | a pumpkin contains seeds |
OpenBookQA | OpenBookQA-1115 | astrophysics
Title: Is there any way to survive solarwinter like in Sunshine - movie? Is there any way to survive solarwinter like in Sunshine - movie?
Solar winter is where for some reason sun looses its capasity to produce radiation( heat etc.). It doesn't loose everything but some of its radiation energy( say 50 %) That causes earth to cool down causing next "ice age" Food could be grown using UV lights, powered by nuclear fission.
We could probably do it.
But it would be the spece equivalent of a human being on a life support machine - all our time and energy would be consumed just with survival, so while humans as a species might survive, our society, culture and science would probably slow down to a crawl, or disappear completely. Most other species would die off, so it would be a pretty dismal future.
The following is multiple choice question (with options) to answer.
In order to conserve energy and eat less through winter, what kind of animal or insect hibernates? | [
"Chairs",
"Birds",
"Humans",
"Bees"
] | D | if an animal relies on plants for food then that animal must store enough food to last through the winter |
OpenBookQA | OpenBookQA-1116 | homework-and-exercises, fluid-dynamics, flow, bernoulli-equation, lift
Title: Is it possible to lift a bald person with an airstream? (Coanda effect and Bernoulli's principle) Lately, a high school teacher called Bruce Yeany has been uploading some fluid dynamics demonstrations on his YouTube channel. Here's his first demo video using various objects like vegetables and containers. He's also uploaded a follow-up demo with dolls.
There's a comment thread at the time of writing on that second video about whether or not it would be possible to lift an actual bald person using a rapid airstream.
I wasn't sure how to start, so here are my assumptions:
the person has average body proportions
the head of a bald person is roughly three quarters of a sphere (at the back)
the radius of that sphere is $r_{head}$ of about $8$ cm
the mass of the person is $m_{person}$ of about $80$ kg
atmospheric pressure of $1013$ hPa
airstream velocity $v_{air}$ (variable)
The following is multiple choice question (with options) to answer.
A disperser is able to | [
"leave things",
"break things",
"redirect things",
"shorten things"
] | C | a disperser disperses |
OpenBookQA | OpenBookQA-1117 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
herbivores do what with plants | [
"burn them",
"garden them",
"trade them",
"snack on them"
] | D | herbivores only eat plants |
OpenBookQA | OpenBookQA-1118 | # Thread: physics tourist & bear problem
1. ## physics tourist & bear problem
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
2. Originally Posted by rcmango
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
The maximum value of d is such that the bear gets to the car at the same time the tourist does.
So set up a coordinate system such that the bear is at the origin and positive x is in the direction from the bear to the tourist.
Both are moving at a constant speed. The bear has to cover 27 + d meters in the same time the tourist covers d meters.
So for the tourist:
[tex]d = v_t t = 3.5t[tex]
Thus
$t = \frac{d}{3.5}$
For the bear:
$27 + d = v_b t = 6 \left ( \frac{d}{3.5} \right )$
Now solve for d.
-Dan
3. Hello, rcmango!
Another approach . . .
A tourist being chased by an angry bear is running in a straight line
toward his car at a speed of 3.5 m/s. .The car is a distance $d$ meters away.
The bear is 27 meters behind the tourist and running at 6.0 m/s.
The tourist reaches the car safely.
What is the maximum possible value for $d$?
The tourist has a 27-meter headstart.
Relative to the tourist, the bear has a speed of 2.5 m/s.
To cover 27 meters, it takes the bear: . $\frac{27}{2.5} \:=\:10.8$ seconds.
The following is multiple choice question (with options) to answer.
A white bear lives in a place that is | [
"hot",
"cold",
"dark",
"dense"
] | B | polar bears live in cold environments |
OpenBookQA | OpenBookQA-1119 | thermodynamics, water
Title: Latent heat and energy transfer Inside an insulated vessel at 1atm there is water at 100°C and a metal rod at 100°C, since temperature gradient is null there is no net heat transfer and water still liquid. In other words, in order to transmit latent heat, there must be a temperature difference. Am I right ?
In other words, in order to transmit latent heat, there must be a
temperature difference. Am I right ?
That is correct. Heat is energy transfer due solely to temperature difference.
Since you asked this question specifically in connection with latent heat, I think you may be confusing the requirements for heat transfer to occur with the results of that heat transfer in terms of temperature changes.
If the rod was at a temperature greater than 100 C then it could transfer heat to the water. But since the water is at its boiling point that transfer would not initially cause an increase the temperature of the water. Instead it would convert some liquid water to vapor vapor (steam) at constant temperature and pressure. That heat is then called the latent heat of vaporization.
On the other hand, if the water was below 100 C at 1 atm, heat transfer from the rod to the water would initially increase the temperature of the water until it reached its boiling point. The amount of heat required to raise the temperature of the water would be determined by the specific heat of water.
Hope this helps.
The following is multiple choice question (with options) to answer.
As a liquid's temperatures get hotter | [
"ice cream will deliquesce faster when the liquid is poured over it",
"rocks will melt faster when the liquid is poured over it",
"the liquid will harden as it's poured",
"the liquid will cool down anything it touches"
] | A | as temperature increases , the ability of that liquid to dissolve solids will increase |
OpenBookQA | OpenBookQA-1120 | geophysics, seismology, instrumentation
Title: How can I calculate the sensitivity of a seismometer? I would like to know if a specific seismometer can measure 1 micron/sec velocity. I have a few specs from the datasheet but I'm not a seismologist and am trying to figure out how to relate the specs to one another.
I have:
Velocity output band: 30s (0.03Hz) to 100 Hz
Output Sensitivity: 2400 V/m/s
Peak/Full scale output: Differential: +- 20V
Sensor dynamic range: 137 dB @ 5 Hz
Thanks in advance! This is a partial answer because I'm not an expert and because I don't know what the dynamic range of 137 dB means. Hopefully you can add a little more information.
tl;dr: if 137 dB is the dynamic range in power, then it's 68.5 dB in voltage and velocity which sounds more plausible, and makes the velocity sensitivity well below 1 micron per second. However we don't yet know what the noise and bandwidth of your signal are yet so we can't evaluate that.
I have a few specs from the datasheet...
The more information you share from the data sheet the better although I've now just noticed that the question is about three years old.
Also, there may be some helpful insight at How sensitive are typical seismometers?
The following is multiple choice question (with options) to answer.
What does a seismograph measure? | [
"the motion produced by underground collisions",
"the quaking of a man in fear",
"how strong the earth quakes beneath a stampeding herd",
"how strong waves can break plates"
] | A | a seismograph is used for measuring the size of an earthquake |
OpenBookQA | OpenBookQA-1121 | climate-change, sea-level
Title: Is sea erosion the opposite of sea level rising (or rather, an adjacent phenomenon)? Because I understand the mechanism of sea erosion as to take earth away from shorelines (and scatter it deep into the sea floor) and also to derive from climate crisis, I ask the following question:
Is sea erosion the opposite of sea level rising (or rather, an adjacent phenomenon)? A paper about this was published yesterday in Nature Climate Change: Sandy coastlines under threat of erosion (Vousdoukas et al. 2020).
While shoreline change can be the combined result of a wide range of potentially erosive or accretive factors, there is a clear cause and effect relationship between increasing sea levels and shoreline retreat, pointing to increased coastal erosion issues. Climate change will also affect waves and storm surges, which are important drivers of coastal morphology.
The study computes projections of shoreline retreat. They computed four projections: two for 2050, and two for 2100, depending on climate change scenarios (RCP 4.5 and RCP 8.5). Here are the results:
Assuming that there are no physical limits in potential coastal retreat, by mid-century we project a probable (5th–95th percentile) global average long-term shoreline change, ranging from –78.1 to –1.1 m and –98.1 to 0.3 m, under RCP 4.5 and RCP 8.5, respectively (negative values express erosion). By the end of the century the erosive trend becomes even more dominant and we project a probable range from –164.2 to –14.8 m and –240 to –35.3 m under RCP 4.5 and RCP 8.5, respectively.
And here is how it looks on a map (their figure 1):
The caption reads:
Projected long-term shoreline changes. a–d, Projected shoreline
changes by the years 2050 (a,c) and 2100 (b,d) under RCP 4.5 (a,b) and
RCP 8.5 (c,d). Values represent the median change and
positive/negative values, respectively, express accretion/erosion in
metres, relative to 2010. The global average median change is shown in
the inset text for each case, along with the 5th–95th percentile
range.
The following is multiple choice question (with options) to answer.
which of these would result in reversal of desertification? | [
"sowing a seed for each felled tree",
"cutting down as many trees as possible",
"taking all the water away from deserts",
"all of these"
] | A | a tree can be replaced by planting a new tree |
OpenBookQA | OpenBookQA-1122 | acoustics, air, displacement
\end{align}$$
That is a Very Loud Pop - about 80 dB. Even if we argue that only a small fraction of this pressure ends up in the audible range there is no doubt in my mind you would hear "something".
So yes, you can hear that parchment disappearing. No problem. Even if some of my approximations are off by a factor 10 or greater. We have about 5 orders of magnitude spare.
AFTERTHOUGHT
If you have ever played with a "naked" loudspeaker (I mean outside of the enclosure, so something like this one from greatplainsaudio.com):
The following is multiple choice question (with options) to answer.
Where would you hear sound reflecting off surfaces? | [
"canyon",
"outer space",
"in the ocean",
"in a vacuum"
] | A | echo is when sound reflects off of a surface |
OpenBookQA | OpenBookQA-1123 | thermodynamics, perception
Title: Our Perception of Heat Our body temperature is roughly 37 degrees celsius (that is, when we measure our body temperature externally, by using a thermometer that measures the temperature of our skin usually between our arm and side torso), whereas most of us would say that 25 degrees would be a pretty hot day. Why do we perceive a 25 degree day to be hot, when thermal energy from our 37 degree bodies should be leaving out and entering our surroundings? You are correct in a sense of thermodynamics. The heat from a human body does indeed leave the body and into the surroundings. The body combats this by burning calories and producing more heat, keeping the internal body at a constant temperature.
I'm not a biologist however:
Perception of a hot day, is just because our nerves our telling our brain its a given temperature. We are warm blooded animals, our body naturally generates heat. Lets assume that the body generates the same amount of heat every day, our brain may interpret a 25C day as warm because the body is generating the same amount of heat however it is leaving the body into the surroundings at a slower rate.
Temperature sensing is a survival tool, it used as a way of keeping the body at a constant temperature. As it gets hotter, your brain is in a sense telling you that it's getting harder to cool. (Forgive my terminology)
Think of this, if the day was as hot as the human body, you would be at danger of heat stroke.
The following is multiple choice question (with options) to answer.
What temperature is most likely to result in sweat? | [
"0 degrees Celsius",
"95 degrees Fahrenheit",
"34 degrees Celsius",
"33 degrees Celsius"
] | B | sweat is used for adjusting to hot temperatures by some animals |
OpenBookQA | OpenBookQA-1124 | gene-expression
Title: How does a gene "know" what to change to? Excuse my ignorance but I've always been curious about this...
For example, a frog is red, but it starts living in a green forest. Over time the frog becomes green to camouflage. But a gene can't see and I'm sure there's no mechanism for color info to be transmitted to individual genes from the brain. So how does a gene know to pick green over, say, blue? Using your example, the gene doesn't know anything. Mutations cause some of the offspring of the red frog to turn green, some to turn blue, some to turn fluorescent yellow, and some stay red. Birds can't see the green ones as well as the others, so more green frogs survive and make more green frogs. The red frogs, the fluorescent yellow ones, the blue ones, mostly get eaten. After a few generations, almost all the frogs are green -- not because the gene knew anything, not because the mutations went in any direction, but because all the other changes were counterproductive and got eaten.
The gene doesn't know anything. It's just a bunch of chemicals that randomly react with cosmic rays, chance, whatever. Most of the changes are irrelevant or actively bad, and the frog that's carrying those particular chemicals doesn't survive. But sometimes the change benefits the frog carrying the particular chemicals and then the frog sends those chemicals down to its progeny.
Obviously this is hugely over-simplified. A short and simple intro to the basics of evolution is Understanding Evolution, by UC Berkeley.
The following is multiple choice question (with options) to answer.
when a tadpole changes into a frog, the tadpole is like | [
"a maggot",
"a lamb",
"water",
"a grape"
] | A | tadpole changes into a frog |
OpenBookQA | OpenBookQA-1125 | zoology, mathematical-models, software, imaging
Title: What would it take to recognize a deer by its photo? I am trying to recognize a deer by its antlers or any other means.
Elaborating:
I was hoping to use their antlers to recognize them but I have heard that most deers shed their antlers every year so it would be difficult to recognize it from the last year's photo unless these antlers retain the same pattern every year.
If not the antlers, what other characteristics should I be looking for?
Is there any software that can help me in recognizing a deer? There is a lot of variation in how and when deer shed their antlers. In most arctic and temperate-zone species, antler growth and shedding is annual, and is controlled by the length of daylight. In tropical species, antlers may be shed at any time of year, and in some species such as the sambar, antlers last several years. Some equatorial deer never shed their antlers.
The horns change every year and, especially, increase the number of branches (and consequently, change their shape). You can't recognize them by antlers, but by other features, such as color of the hair or the lineaments. Like us, animals have individual morphological differences that are recognizable and listable.
Biologists specializing in studies of particular animal species not only take photos, but also make drawings and write descriptions of behavior, to identify individuals within herds.
An optical examination, however, of the subject through drawings and photos (and if possible, direct observation), is more useful than a PC program. This involves identifying particular similarities and equalities that are not "identical". This is possible to do visually on a large (but limited) number of specimens. The human eye is the best computer.
The following is multiple choice question (with options) to answer.
Shedding is when an animal? | [
"gets rid of its winter coat",
"grows taller",
"speaks at a higher volume",
"eats its food"
] | A | shedding is when an animal loses hair |
OpenBookQA | OpenBookQA-1126 | electromagnetism, magnetic-fields, electromagnetic-induction, batteries
Title: How this toy shown on YouTube works and can the coil be replaced by a hollow magnetic thorus? I saw this video on YT and what I can not figure out is why the coil used in the arrangement could not be replaced by a hollow magnetic torus? Notice that the magnets are attached to the ends of a battery (the source of power). To experience a net force, the magnets must be in a non-uniform magnetic field. In this case the magnets conduct current, to the coil, which flows only between the magnets. A short segment of hollow magnetic torus produces a field which spreads rapidly at the ends and thus exerts a force on the magnets which are at each end of the energized segment. One would need to be careful that the magnets are oriented so that both forces are in the same direction. In this system, the current is mainly limited by the internal resistance of the battery, and may be relatively large. The battery will be drained quickly. A magnet acts as though it has a current flowing around its outer surface. If we take a side view and assume that the field from the coil is spreading out from its right end (the “north pole”), and we place a magnet so that its current flows away from us on the top (putting its north pole on the left), then the vertical component of the field will push the current on top of the magnet to the right, and the current on the bottom will also be pushed to the right. (This kind of analysis can also be applied to the microscopic currents associate with each atomic dipole using the divergence of the field). On the left end of the activated section of the coil, the field is coming in, the vertical components are reversed, and to keep the net force to the right, the magnet would need to be reversed. If you think of both magnets as being just outside of the ends of the activated coil, the north pole of the magnet is being repelled by the north pole of the coil on the right, and the north pole of the magnet is being attracted by the south pole of the coil on the left. (A compass needle can be used to determine which ends are north or south.)
The following is multiple choice question (with options) to answer.
What will become magnetic in an electromagnet if the battery becomes active? | [
"A construction nail",
"A plastic nail",
"A nail box",
"A wooden nail"
] | A | if battery in an electromagnet is active then the nail in the electromagnet will become magnetic |
OpenBookQA | OpenBookQA-1127 | biochemistry, botany, plant-physiology, photosynthesis
What are typical characteristics of different plants in this regard? I.e., how do common species of plants manage their C consumption before (and after) the development of leaves? There are quite a few questions and thoughts in there, I'll try to cover them all:
First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons).
You are correct to assume the C is further used for the growing process; it is used to make sugars which store energy in their bonds. That energy is then released when required to power other reactions, which is how a plant lives and grows. C is also incorporated into all the organic molecules in the plant.
Plants require several things to live: CO2, light, water and minerals. If any of those things is missing for a sustained period, growth will suffer. Most molecules in a plant require some carbon, which comes originally from CO2, and also an assortment of other elements which come from the mineral nutrients in the soil. So the plant is completely reliant on minerals.
Most plants, before a leaf is established or roots develop, grow using energy and nutrients stored in the endosperm and cotyledons of the seed. I whipped up a rough diagram below. Cotyledons are primitive leaves inside the seed. The endosperm is a starchy tissue used only for storage of nutrients and energy. The radicle is the juvenile root. The embryo is the baby plant.
The following is multiple choice question (with options) to answer.
Plants require | [
"oxygen",
"H2O",
"Fe",
"clouds"
] | B | a plant requires water to grow |
OpenBookQA | OpenBookQA-1128 | neuroscience, neurophysiology, memory, cognition
References
- Kuhl et al., Nature Neurosci (2007); 10: 908-14
- Shea & Right, Res Quarterly Exercise Sport (1991); 62(3)
- Stronks et al., Brain Res (2015); 1624: 140–52
The following is multiple choice question (with options) to answer.
A woman wants to make sure that she can physically look back over memories of a day, as they progress, whenever she wants, so she | [
"brings a phone",
"brings a camera",
"brings a book",
"brings a lunch"
] | B | a camera is used for recording images |
OpenBookQA | OpenBookQA-1129 | species-identification, botany
Title: Which strange fruit is this? Yesterday, my brother brought a strange fruit resembling Lychee (but much bigger in size). Here is a pic of it:
When cut it, it had smell like banana and fibers were like of the chicken meat, though taste was more or less like banana (sorry have no pic of that).
Can someone kindly help me identify it? This appears to be a jackfruit. Jackfruit are a large, tropical fruit, commonly reported as smelling similar to banana.
The following is multiple choice question (with options) to answer.
An animal that may like a banana peel is a | [
"bear",
"raccoon",
"cat",
"dog"
] | B | raccoons eat waste |
OpenBookQA | OpenBookQA-1130 | acoustics, air, displacement
\end{align}$$
That is a Very Loud Pop - about 80 dB. Even if we argue that only a small fraction of this pressure ends up in the audible range there is no doubt in my mind you would hear "something".
So yes, you can hear that parchment disappearing. No problem. Even if some of my approximations are off by a factor 10 or greater. We have about 5 orders of magnitude spare.
AFTERTHOUGHT
If you have ever played with a "naked" loudspeaker (I mean outside of the enclosure, so something like this one from greatplainsaudio.com):
The following is multiple choice question (with options) to answer.
A way in which sound may be heard is | [
"eating out of a bowl",
"moving pots and pans",
"moving a cardboard box",
"a small plastic cup"
] | B | matter vibrating can cause sound |
OpenBookQA | OpenBookQA-1131 | entomology
Title: Constantly wiggling moth pupa - will it emerge soon? Today I found a moth pupa in the soil in my garden in western Sweden. It's about 15 mm long.
I have found similar ones before, but this one is wiggling a lot more, even after I put it down and put a bit of dirt over it. It's been moving for more than an hour now, but less now than in the beginning.
I was hoping to see it emerge, but if it will take more than a day or so, I will probably put it back. So, what I'm wondering is if this wiggling is any indication of how soon it will emerge. Or if there are other ways to tell.
Update: an hour later it has stopped moving. Maybe it was just very disturbed by my presence. I'm keeping it in a jar with soil and a stick for climbing up on, and I'll decide what to do with it tomorrow.
Update: 12 hours later and it seems very still. But I'm letting the question remain since I really want to know if there are any signs to look for.
Final update: After 16 days it had turned almost black, and was still very active when handled.
And after 17 days this moth came out: I posted the same question on tumblr and got an answer:
It depends on the species. This one looks like a Noctuid. I’d give it
two weeks to a month or so. You may be able to see its wings showing
through the darkening pupal case when the time draws near! Just make
sure you give it somewhere to climb up and expand its wings when it
ecloses.
After keeping it until the moth emerged, I now know that wiggliness is not an indication of maturity, but turning dark is.
The following is multiple choice question (with options) to answer.
To survive some moths have developed | [
"loud voices to scare off predators",
"prehensile thumbs to help them grab things",
"large wings that make them more visible",
"wing patterns that allow them to blend into with leaves"
] | D | adaptation is when an organism develops a trait over time for survival |
OpenBookQA | OpenBookQA-1132 | It helps to try out the strategy with a smaller number of students. With only five students you teacher's method gives $$4^5-\binom{4}{1}\cdot3^5+\binom{4}{2}\cdot2^5-\binom{4}{3}\cdot1^5=1024-972+192-4=240$$ ways. You can check that this is right by observing that some book must be distributed to two students and each of the other books to only one. There are four choices for which book goes to two students, and $$\binom{5}{2}$$ choices of the two students, and $$3!$$ ways to distribute the other three books to the remaining students: $$4\cdot10\cdot6=240$$.
Now try your method, which gives $$\binom{5}{4}\cdot4!\cdot4^1=480$$ ways. Why is your number too big? It's because distributing different books to students $$1$$, $$2$$, $$3$$, $$4$$ and any book to student $$5$$ includes some of the same configurations as distributing different books to students $$1$$, $$3$$, $$4$$, $$5$$ and any book to student $$2$$. For example, if students $$1$$, $$2$$, $$3$$, $$4$$ get $$H$$, $$R$$, $$L$$, $$E$$ in that order and student $$5$$ gets $$R$$, that's the same as students $$1$$, $$3$$, $$4$$, $$5$$ getting $$H$$, $$L$$, $$E$$, $$R$$ in that order and student $$2$$ getting $$R$$.
The following is multiple choice question (with options) to answer.
which of these students will see the teacher larger? | [
"a boy sitting in front",
"a girl in the back",
"a boy outside the class",
"a girl in the middle"
] | A | as distance to an object increases , that object will appear smaller |
OpenBookQA | OpenBookQA-1133 | zoology, ecology, diet, predation
Cheetahs have been reported to suffer from intraguild competition by lions Panthera leo, spotted hyenas Crocuta crocuta and occasionally leopards Panthera pardus. These larger predators represent a threat to the smaller-bodied cheetahs as they can affect their food intake by limiting access to high resource areas or kleptoparasitism (e.g. 10–12% of kills are kleptoparasitized in Serengeti National Park (SNP)), and reduce population sizes via increased cub mortality (e.g. 73% of cub mortality was due to predation in the SNP). In response, cheetahs often demonstrate avoidance behavior to minimize interactions with dominant carnivores , with spatial and temporal partitioning regarded as the principal behavioral mechanisms by which this is achieved. Accordingly, cheetahs have been described as a refugial species that seeks competition refuges within the landscape with low densities of lions and spotted hyenas.
Rostro-García S, Kamler JF, Hunter LT. To kill, stay or flee: the effects of lions and landscape factors on habitat and kill site selection of cheetahs in South Africa. PLoS One. 2015;10(2):e0117743. Published 2015 Feb 18. doi:10.1371/journal.pone.0117743
(removed the citations)
The definition of the terms used in the above citation:
Intraguild predation, or IGP, is the killing and sometimes eating of a potential competitor of a different species. This interaction represents a combination of predation and competition, because both species rely on the same prey resources and also benefit from preying upon one another. - Wikipedia
Kleptoparasitism, literally meaning parasitism by theft, is a form of resource acquisition where one animal takes resources from another. Although kleptoparasitism of food (i.e., kleptoparasitic foraging) is the best known example, the stolen resources may be food or another resource such as nesting materials. - Sciencedirect.com
The following is multiple choice question (with options) to answer.
Lions eat animals | [
"in a different environment from where they live",
"in the water",
"underground",
"in the same environment where they live"
] | D | most predators live in the same environment as their prey |
OpenBookQA | OpenBookQA-1134 | = ",Count[Drop[branches,gen],_Real,\[Infinity]]/4" "" ""Length = ",SetAccuracy[Count[Drop[branches,gen],_Real,\[Infinity]]/4*(Norm[{{pt1[[1]],0.5},{0,0}}]^gen),3]}],18],Gray],{2.3,-1.8}]},{Inset[Style[Text@TraditionalForm@Style[Row[{"Polynomial Trees by Bernat Espigulé"}],18],Gray, Opacity[0.4]],{2.3,-2}]}},PlotRange->{{-1.7,3.7},{-2.1,1.5}},ImageSize->{1000,600},Background->Black]],{{th,0.025,"Thickness"},0.005,0.185},{{gen,12,"Generations"},Range[1,16], ControlType -> SetterBar},{{pt1,{0.5,0.5}},{-0.5,0.5},{0.5,0.5},Locator}]Jurassic Trees
The following is multiple choice question (with options) to answer.
Cutting down a tree | [
"ceases its ability to grow",
"will cause it to grown 10x bigger",
"will decrease the likelihood of deforestation",
"will cause the tree to flourish"
] | A | if a tree is cut down then that tree will die |
OpenBookQA | OpenBookQA-1135 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
Where do soil nutrients also exist? | [
"in organism foods",
"in the air",
"in the barn",
"in the water"
] | A | if some nutrients are in the soil then those nutrients are in the food chain |
OpenBookQA | OpenBookQA-1136 | species-identification, microbiology, microscopy
Title: Identification of protozoa under microscope I observed maybe Protozoa from standing FRESH water and from slowly flowing FRESH water. I am complete dilettante. Can you tell what these creatures are?
https://www.youtube.com/watch?v=6D5ck3zNJzA&t=474s
Thank you.
Added picture for to be more specific At first glance, the organisms may hold the appearance of protozoans like ciliates. However, I am of the belief that these 'totally tubular' micro organisms are in fact diatoms.
The diatoms are a diverse range of eucaryotic microalgae which comprise a large percentage of the phytoplankton group. (Diatomaceous earth is the residual remains of their calcareous walls)
They are likely diatoms because of their apparent hard membrane, and slight brown-green pigment, typical of heterokont diatoms.
I would be unable to specify the organism to family level. However, you may wish to complete your investigation by looking under the order 'Pennales'.
For general information regarding the Diatoms, you may visit https://en.wikipedia.org/wiki/Diatom
Morphology and description available from: https://books.google.co.uk/books?id=xhLJvNa3hw0C&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
Good luck
The following is multiple choice question (with options) to answer.
what role does some plankton have that is similar to farmer in ohio? | [
"needs food",
"produces food",
"can get sick",
"lives in ocean"
] | B | In the food chain process some types of plankton have the role of producer |
OpenBookQA | OpenBookQA-1137 | kinetics, energy, food-chemistry, fuel
Title: Is it possible to turn food into fuel for a combustion engine? According to McDonald's Nutrition Calculator page, the following order would contain 2480 kilocalories (or 10376 kilojoules):
1 x Double Bacon Smokehouse Burger
1 x Large Chocolate Shake
1 x Large World Famous Fries®
Would it be possible to somehow extract/convert that energy and use it to power a car engine? If so, what would be the involved chemical processes, equations and byproducts?
Note that this question is entirely motivated by curiosity and by an ingenuous notion of Lavoisier's principle of mass conservation. You can combust all you have and obtain 10376 kJ (human will obtain less energy, because we are not campfires to burn everything indiscriminately). But, instead, you can be a little bit more smart and combust fats of the same mass, which give 38 kJ per gram (proteins and carbohydrates give less than half of it). This idea allows you to use less fuel for same productivity. Actually, the idea is already widely used - check for biodiesel. Source below gives detailed basic-level insight.
Biodiesel are produced through a simple technology called trans-esterification reaction. Degummed oil free of all forms of impurities is reacted with a reasonable alcohol (ethanol, methanol, butanol etc.).
Citation source:
Biodiesel: Fuel for the Future (A Brief Review). Owolabi R. U., Adejumo A. L., Aderibigbe A. F. International Journal of Energy Engineering 2012; 2(5): 223-231.
DOI: 10.5923/j.ijee.20120205.06
The following is multiple choice question (with options) to answer.
Which of the following might use Chia to fuel it? | [
"Bird",
"Kite",
"Plane",
"Jet"
] | A | birds sometimes eat seeds |
OpenBookQA | OpenBookQA-1138 | behaviour
Title: What happens to silverfish when we throw them out the window? I'll find a silverfish from time to time in my flat. I don't mind them but usually I catch them and throw them off the balcony (second story) into the bushes and lawn below.
I was wondering, since they seem to live in the water conduits in the house, if they can survive outside or if they die/get killed instantly.
Thx for your help! Silverfish prefer high humidity and warmth. Ctenolepismacalvum (Ritter, 1910) was recently found in Japan at a temperature of 20-30°C and 50-60% RH. As long as there are pieces of bark, wet grass or other organic or human-made structures that retain humidity after each raining event, the likelihood that they will survive long enough to complete their cycle is high.
They could face dessiccation if they are not able to find a damp spot in time, depending on their tolerance to it. However, it was not possible for me to find information about their dessiccation tolerance.
The Zygentoma (silverfish order) have high tolerance to low humidity and most of the species inhabit dry and hot environments (it's just a few that like humidity), which again makes me think that those silverfish propelled out the window will survive.
The following is multiple choice question (with options) to answer.
Events like thunderstorms and _______ can cause animals to leave an environment. | [
"car crashes",
"solar eclipses",
"more available food",
"tsunamis"
] | D | natural disasters can cause animals to leave an environment |
OpenBookQA | OpenBookQA-1139 | photosynthesis
Title: Photosynthesis in oxygen free enviornment If a plant is grown in an oxygen free enviornment would it live longer in light or darkness?
It is evident that oxygen would compete with carbon dioxide during various processes like competing with carbon dioxide for reducing power, also oxygen quenches the excited electron of chlorophyll etc.
But all these effects to me don't give any sense of the extent of oxygen on these reactions. What does the absense of oxygen have on the system? Except ofcourse the plant not being able to respire properly. If that "environment" is a closed vessel or bell-jar; certainly the plant would survive in light (when it simultaneously perform respiration and photosynthesis), and in darkness (when it can perform only the respiration) it would survive upto certain time due to the oxygen it accumulated. But should die at prolonged darkness when the plant would finish all the oxygen.
(as suggested by Priestley's classic 1870 experiment * there was enough oxygen to keep a mouse for certain time)
(image link)
However, if we look the effect of various concentration of O2 on photosynthesis rate without altering the CO2 concentration; yes the photosynthesis rate get affected; one known effect is called Warburg effect or Inhibition of photosynthesis by O2.
In this effect, photosynthesis rate only decrease if O2 concentration is increased. And in vice-versa, with O2 concentration decrease, photosynthesis rate only increase. (source: this, this, this and this)
This take place due to mainly 2 causes: 1. O2 work in competitive way with CO2 for binding with the enzyme RuBisCO, the key enzyme for CO2 fixation in plants. 2. And that induces photorespiration (in C3 plants). (Wikipedia shows reference to here). (However this old paper also tells other hypotheses)
The following is multiple choice question (with options) to answer.
A plant performs less photosynthesis in | [
"September",
"March",
"December",
"June"
] | C | a leaf absorbs sunlight to perform photosynthesis |
OpenBookQA | OpenBookQA-1140 | mountains, rainfall
Title: Could a waterfall lashing onto a road lead to a landslide? Here is a video of a waterfall lashing on to a mountain road, with vehicles driving under it.
https://youtu.be/cHaguj--YBc
There appears to be a big hole carved out right next to the road, possibly by the force of the waterfall.
Is this a ticking time bomb for a landslide? Potentially, a landslide could occur. Whether it would be a minor slip or a major fall depends on the geological conditions at the site, the force of the water and the duration that the site is impacted by the water.
In the video in question, the rock face above the road appears competent, but there are not guarantees. The main issue would be is the water undermining the road which could cause a slip and the road to slide.
The more loose the geological material is, the easier it is to dislodge it. Once one item moves a chain of events can occur where additional items are dislodged and a slide occurs.
In addition to high pressure water dislodging material, water acts as a lubricant, making it easier for rocks and regolith to be dislodged.
To minimise the potential for a slide to occur in such a situation, the surface of the road would need to be sealed very well and a very good drainage system installed that would move the water away from the road and the slope below the road
The following is multiple choice question (with options) to answer.
A landslide has | [
"Multiple causes",
"Unicorns",
"Airplanes",
"Fires"
] | A | landslides often occur on mountains |
OpenBookQA | OpenBookQA-1141 | geophysics, climate-change, glaciology
As we can see from the chart, there's been a pretty steady drop in CO2 PPM over the last 15 million years or so. As the ocean grows colder it can store more CO2 so there may be a correlation between falling temperature and falling CO2 PPM - one of the primary climate feedback mechanisms, but predicting future CO2 levels - I wouldn't even know what to guess. Certainly low enough CO2 PPM could lead to further ice ages, even after Antarctica drifts off the south pole, so, there's the problem - too many unknowns. This question has no answer.
A 4th possible key driver would be ocean currents, as indicated by the theory that the formation of the Isthmus of Panama may have been a key driver in the current ice age cycle, but predicting ocean current changes millions of years into the future is above my pay grade.
The 3 primary drivers do seem to fit past ice ages.
The the Andean-Saharan ice age period 425-450 million years ago, CO2 levels were much higher but that long ago the sun was perhaps 3%-4% less luminous and much of the land was over the antarctic circle.
The Karoo ice age period is associated with a drop in CO2 and an increase in O2 (Source)
That probably long and rambling and needs more than a little clean-up and I invite counterpoints, but I think that's the gist of estimating when ice ages will end. A precise answer isn't possible.
The following is multiple choice question (with options) to answer.
If a climate becomes colder over time | [
"bears that have sparse fur with thrive",
"bears that develop thin pelts will thrive",
"bears that carry little fat will thrive",
"bears that grow heavier pelt will survive"
] | D | changes in an environment cause animals to adapt to survive |
OpenBookQA | OpenBookQA-1142 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Earlier in their lives many amphibians ate | [
"meat",
"flies",
"beetles",
"algae"
] | D | tadpole changes into a frog |
OpenBookQA | OpenBookQA-1143 | geology, fossil-fuel, petroleum
For some transport applications, the energy density is still a winning attribute of hydrocarbons: most notably, powered flight for freight and travel.
We already have two routes to non-fossil hydrocarbons: biological sources, and direct chemical synthesis. Each involves capturing atmospheric CO2, and combining with water, to generate a blend of hydrocarbons.
Now, we already have means of creating hydrocarbons suitable for flight (e.g. Jet-A and Jet-A1 fuels). And there are already demonstration plants that have closed-loop generation of synthetic hydrocarbons, for use in electricity-grid-balancing, by using surplus electricity to synthesise methane, which is then burnt in gas turbines when required. Similarly, Tony Marmont's team have been synthesising petrol (gasoline) from air, water, and electricity.
However, none of those things mean that hydrocarbons necessarily have much of a future, beyond plastics production. Because hydrocarbon-powered aviation has a lot of environmental problems beyond just CO2 emissions, in particular it makes other contributions to exacerbating global warming. And there are lots of options for energy storage within the electricity supply chain.
The following is multiple choice question (with options) to answer.
Fossil fuels | [
"are a renewable resource",
"have an unending supply",
"can last for eons in the future",
"are a dwindling commodity"
] | D | fossil fuels are a nonrenewable resource |
OpenBookQA | OpenBookQA-1144 | food-chemistry
popcorn (kernels)
honey (jar of)
sugar (most forms)
alcohol (spirits like vodka, whiskey)
dried beans, dried lentils
I would not be planning to eat any of these stored for 25 years myself. And in general I'd suggest testing the items before trying them after 25 years or more (if you feel you must).
I would not expect cans or glass or plastic bottles of soda to be in good shape after anything like 25 years. The plastic might not survive without degrading. The can and plastic might react with the liquid over that timescale and the glass would survive but I'd be less optimistic about a sugar laced chemical soup like soda or cola not undergoing some changes. Hard to say.
If you want more info on this try this website.
Will it be ok to drink it, if it won't explode?
I would not try it. At best it soda would be flat and possibly not taste the same (chemical changes over that timescale ?) and at worst it could actually be harmful.
Exploding seems very unlikely.
Also, what about Snickers or a hamburger in a ziploc package with air sucked out of it with vacuum cleaner?
Air isn't the issue. There are bacteria that will happily live (and increase in numbers) on what's in the food. Well, it is food, after all. There are bacteria that will survive refrigeration as well. Over the timescale you're talking about I'd say it's all bets are off territory.
So: will Snickers, Hamburger in a ziploc, Bottle (or can) of Cola, all not opened, go crazy in 25 years? In 50 years?
All of those could be dangerous over such a long time period, IMO. At the very least they'd taste bad and at worst they'd kill you if you consumed them.
If so, can they go out of their packages and ruin the contents of the time capsule? If not, will it be safe to consume one of them?
Depends on the packaging. Glass would last indefinitely baring physical force or extreme of hot and cold (which might possibly cause fatigue cracking). The other wrappers would last pretty well (structurally), but 25 years is way past their design intentions. It would be a dice throw.
The following is multiple choice question (with options) to answer.
Consuming a hot liquid can | [
"Remove years of rust on a knife",
"sooth a pained esophagus",
"Cleanse the soul for God",
"Cure blindness in a child"
] | B | if liquid is boiling then that liquid is hot |
OpenBookQA | OpenBookQA-1145 | java, reinventing-the-wheel, console, unix
With clothes the new are best, with friends the old are best.
He is truly wise who gains wisdom from another's mishap.
Beware of a dark-haired man with a loud tie.
Today is the last day of your life so far.
Flee at once, all is discovered.
Man who falls in vat of molten optical glass makes spectacle of self.
Go directly to jail. Do not pass Go, do not collect $200.
For a good time, call 8367-3100.
Those who can, do; those who can't, simulate.
Those who can, do; those who can't, write. Those who can't write work for the Bell Labs Record.
God does not play dice.
This fortune is inoperative. Please try another.
Laugh, and the world ignores you. Crying doesn't help either.
No amount of genius can overcome a preoccupation with detail.
You will feel hungry again in another hour.
You now have Asian Flu.
God made the integers; all else is the work of Man.
Disk crisis, please clean up!
You auto buy now.
Many are called, few are chosen. Fewer still get to do the choosing.
Try the Moo Shu Pork. It is especially good today.
Many are cold, but few are frozen.
The early worm gets the bird.
He who hesitates is sometimes saved.
Time is nature's way of making sure that everything doesn't happen at once.
The future isn't what it used to be. (It never was.)
Can't open /usr/lib/fortunes.
If God had wanted you to go around nude, He would have given you bigger hands.
It is better to have loved and lost than just to have lost.
A journey of a thousand miles begins with a cash advance from Sam.
Disk crunch - please clean up.
Center meeting at 4pm in 2C-543
I will never lie to you.
Spock: We suffered 23 casualties in that attack, Captain.
Your computer account is overdrawn. Please reauthorize.
1 bulls, 3 cows
It's hard to get ivory in Africa, but in Alabama the Tuscaloosa.
Waste not, get your budget cut next year.
Old MacDonald had an agricultural real estate tax abatement.
Snow Day - stay home.
Save gas, don't eat beans.
The following is multiple choice question (with options) to answer.
My dad gave me | [
"my head windows",
"a building",
"air",
"the sun"
] | A | offspring receive genes from their parents through DNA |
OpenBookQA | OpenBookQA-1146 | thermodynamics, climate-science
Title: Where does all the heat go during winter? I do not understand where actually the heat in our surroundings go during the winter season. Is it radiated out into space? I know it cannot coz global warming would not be a issue then. It might get absorbed but where? I tried figuring it myself but couldn't please help.
Where does all the heat go during winter?
There is less energy coming from the sun in the form of electromagnetic radiation impinging on the land during winter.
Depending on the latitude, in regions where there is winter , the difference is large.
The closer to the equator the smaller the effect of "winter".
So it is not where the energy goes, but why it does not fall , and this is explained to first order by the inclination and the distance to the sun during the orbit of the earth.
In general , a body in space radiates energy away the rate depending on various conditions, like green house gases, cloud cover, convection , albedo ...the numbers change . It is the continuous radiation from the sun that keeps replenishing the energy so that the earth does not freeze. During winter at high lattitutes , less energy comes and cold settles.
The following is multiple choice question (with options) to answer.
Snowfall takes place during the winter in what area? | [
"Arctic",
"Atlantic",
"Rain forest",
"Tropics"
] | A | snow falls during the winter in the arctic environment |
OpenBookQA | OpenBookQA-1147 | atmosphere, wind, geography, troposphere, stratosphere
Title: Other than the South Pole where is the windless place on Earth? For this other question "Would this chambered cylinder be possible", preferably near the equator where is a calmest place from the troposphere to the stratosphere where is the windless place one Earth most of the year? Not just the south pole, but 'Ridge A' and many other parts of the high Antarctic Plateau, at or about 4000 metres altitude, are generally recognized as being the least windy. Otherwise, there are a many parts of the high pressure belts at about +/- 30 degrees which have little wind for most of the year. These tend to be very dry deserts where occasional winds have momentum from other regions. On a local scale there are some deep valleys in tropical rain forests. Once you get below the canopy turbulence level they seldom receive winds of any significance - just the lightest breeze from impeded convection. However, records are hard to find because anemometers in such locations are not really representative of anything.
There is an instagram which claims that Fern tree bus stop, in Hobart, Tasmania, is the 'calmest place on Earth'.
But my experience of Hobart is that icy winds in winter can be far from calm.
These things are relative. Compared to the 2100 km/hour winds of Neptune, everywhere on our planet is as close to windless as makes no difference.
The following is multiple choice question (with options) to answer.
Which location does not get snow in the winter? | [
"San Bernardino",
"Sault St. Marie",
"St. Paul",
"St. Louis"
] | A | snow falls during the winter in some environments |
OpenBookQA | OpenBookQA-1148 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
There are nutrients in dirt, like magnesium, and those nutrients may be | [
"poisoned",
"collected into vegetation",
"set on fire",
"taught to read"
] | B | if some nutrients are in the soil then those nutrients are in the food chain |
OpenBookQA | OpenBookQA-1149 | electricity
Title: Why does electricity want to flow into the earth? If I grab hold of a live wire, current will flow through me and into the earth.
If there is an electrical fault in my home, current will flow through the earth wire, out into a ground stake and into the earth.
If enough static electricity builds up in the clouds it will be discharged to the earth through a lightning strike.
What is so special about the earth? Why does current "want" to go there? user253751 said, "[electric current] only flows in loops."
That's true, but what that user didn't say is that the electrical grid is connected to Earth in many places. There is a loop from the transformer outside your house, through the "live" wire, through you, through the Earth, through a long metal stake driven in to the ground near the transformer, and back to the transformer.
The grid is grounded like that to prevent atmospheric phenomena (the same that cause lightning) from building up dangerous static charges on overhead wires.
The current to any small appliance in your home is supplied by two wires. One wire sometimes is known as "hot," and the other is known as "neutral." The neutral wire is connected to Earth. If you touch it, then you won't feel anything. The "hot" wire is the one you don't want to touch. The voltage on the hot wire relative to Earth can be anywhere from around 110 V to 240 V depending on where in the world you live.
The following is multiple choice question (with options) to answer.
If you plug this into an outlet, current will flow through it. | [
"sword tip",
"rubber",
"plastic",
"air."
] | A | sending electricity through a conductor causes electric current to flow through that conductor |
OpenBookQA | OpenBookQA-1150 | astronomy, sun, moon, eclipse
Title: Why don't we see solar and lunar eclipses often? Since we see the new moon at least once in a month when the Moon gets in between of the Sun and the Moon at the night and as far as I know if this happens during the day, you'll get to see a solar eclipse. Why don't we get to see this often or in the day?
Does it mean that in some part of world there's a solar eclipse when we are seeing a new moon? I'm looking for a diagram or interactive way to understand this if possible as I'm not a native English speaker, but I'll try my best to do so. If the Moon's orbit around the Earth were in exactly the same plane as the Earth's orbit around the Sun, we'd have a total solar eclipse every month (but 100% totality would be seen only from the tropics).
But in fact they're not in the same plane. The Earth's spin axis is tilted by about 23 degrees relative to the Earth's orbit around the Sun, and the Moon's orbit is closely aligned with the Earth's spin. As a result, the Sun and the Moon do not follow the same path in the sky.
We get a solar eclipse only when (a) there's a new Moon, so the Sun and Moon are in the same position east-to-west, and (b) the new Moon happens when the Sun and Moon happen to be closely aligned north-to-south.
Since the Sun and Moon are both about half a degree wide (as we see them in the sky), the 23-degree offset of their paths makes solar eclipses relatively rare events.
Lunar eclipses, which occur during the full Moon when Moon passes into the Earth's shadow, are more common because the Earth is bigger than the Moon, and so has a much wider shadow.
The following is multiple choice question (with options) to answer.
If you viewed an eclipse from the moon | [
"You would transport to another dimension",
"It would change time",
"You would be thrown off the moon",
"it would go in reverse"
] | D | the moon orbits the Earth |
OpenBookQA | OpenBookQA-1151 | arduino, wheel, two-wheeled, interrupts
void doEncoderRight(){
if (firstChangeR) delay(1); // if this is the first detection then we wait
// for the bounce to be over
// if the current state is different from the last saved state then:
// a real change happened and it's not part of the bouncing but
// actually the real beginning of the change: the first bounce !
if (digitalRead(2) != right_set) {
right_set = !right_set; // so we change the real state
countR ++; // we also increment the right encoder
// since this was the firstChange the next are part of bouncing, so:
firstChangeR = false;
}
}
void doEncoderLeft(){
if (firstChangeL) delay(1);
if (digitalRead(3) != left_set) {
left_set = !left_set;
countL ++;
firstChangeL = false;
}
}
Tell me what do you think about it? Do you think it's reliable and is there any improvement you can propose?
The following is multiple choice question (with options) to answer.
in order for utility of a tool to occur, what has to happen first? | [
"it needs to be cleaned",
"none of these",
"it needs to be baptized",
"it needs to be invented"
] | D | inventing a tool allows that tool to be used |
OpenBookQA | OpenBookQA-1152 | evolution, taxonomy, ornithology
Title: Birds and Dinosaurs This came up in an argument with some friends. I know that birds are direct descendants of dinosaurs, shown pretty clearly through the fossil record. However, is it proper to say that birds are dinosaurs, or is there an actual distinction? I bet you'll be interested about the concept monophyly. Any human-made group of species (or taxon) like birds dinosaurs, primate, bacteria, angiosperm, reptiles, … are either monophyletic, polyphyletic or paraphyletic. This picture explain the concept When the taxon is monophyletic it is called a clade.
Monophyletic taxon are those groups of species that can be considered to be objective in the sense that it represents a group of species where each species in the taxon is more related (in terms of time to common ancestor, not according to their genetic similarity) to any other species within the same taxon than to any other species outside this taxon. This is obviously not the case for paraphyletic or polyphyletic taxon.
Typically, we do not consider a parrot or a deer to be reptiles. Therefore, the ususal understanding of "reptiles" makes this taxon paraphyletic. Now, one should not confound the common understanding (what is a reptile in our everyday life) with the strict definition of the taxon Reptilia, which is a monophyletic taxon (or a clade in other words). Probably the best source for exploring the tree of life is tolweb.org. Here, you will find the clade Reptilia (who include birds, snakes, turtles and lizards). Note: Mammals are within the Reptiliomorpha, not the Reptilia.
It is exactly the same issue with the dinosaurs. When we talk about dinosaurs in our everyday life we do not mean birds. But there is a clade called Dinosauria, which include both dinosaurs and birds.
In short, I would say that a bird is a Dinosauria (monophyletic taxon) but is not a dinosaur (paraphyletic taxon). But this little play on word is not a scientific issue but an issue of english usage.
You will also find in this post an introduction to phylogeny
The following is multiple choice question (with options) to answer.
A bird eating a lizard is an example of what type of relationship? | [
"symbiotic",
"producer",
"parasitic",
"predatory"
] | D | hawks eat lizards |
OpenBookQA | OpenBookQA-1153 | At the end of the 3rd year the number of trees would be $$(\frac{5}{4})^3*x$$; At the end of the 4th year the number of trees would be $$(\frac{5}{4})^4*x$$; At the end of the $$n_{th}$$ year the number of trees would be $$(\frac{5}{4})^n*x$$; So, we have that $$(\frac{5}{4})^4*x=6,250$$ --> $$\frac{5^4}{4^4}*x=5^4*10$$ --> $$x=4^4*10=2,560$$. Answer: D. If the question were "if all of the trees thrived and there were 6250 trees in the orchard at the end of 15 year period, how many trees were in the orchard at the beginning of the 4 year period", then we would have that: $$(\frac{5}{4})^{15}*x=6,250$$ --> $$x\neq{integer}$$, so it would be a flawed question. Hope it's clear. Isn't the question quite ambiguous, though? I mean the first scentence could be interpreted as "for the first year we have (4/4)x and for the second year (5/4)x and for the third..." etc.. With that reasoning one would have (5/4)^3 * x + x and then your approach doesnt work. Obviously, I understand that this was a flaw in my reasoning but I cannot understand how they - with that wording - will assume that we totally understand that at the end of year one he has (5/4)x.. Is there a straightforward "word translation" way in knowing how to interpret wordings like this? Actually, it is not ambiguous. Read the statement: Each year a farmer increased the number of trees by 1/4. He did this for 4 years. (In GMAT Verbal and Quant are integrated. You need Verbal skills (slash and burn) in Quant and Quant skills (Data
The following is multiple choice question (with options) to answer.
Trees grow growth-rings one time each year; so which of these is correct? | [
"a tree with nine rings is nine years old",
"a tree with six rings is seven years old",
"a tree with eight rings is five years old",
"telling how old a tree is is impossible based on rings"
] | A | a tree growing a tree-growth ring occurs once per year |
OpenBookQA | OpenBookQA-1154 | behaviour
Title: What happens to silverfish when we throw them out the window? I'll find a silverfish from time to time in my flat. I don't mind them but usually I catch them and throw them off the balcony (second story) into the bushes and lawn below.
I was wondering, since they seem to live in the water conduits in the house, if they can survive outside or if they die/get killed instantly.
Thx for your help! Silverfish prefer high humidity and warmth. Ctenolepismacalvum (Ritter, 1910) was recently found in Japan at a temperature of 20-30°C and 50-60% RH. As long as there are pieces of bark, wet grass or other organic or human-made structures that retain humidity after each raining event, the likelihood that they will survive long enough to complete their cycle is high.
They could face dessiccation if they are not able to find a damp spot in time, depending on their tolerance to it. However, it was not possible for me to find information about their dessiccation tolerance.
The Zygentoma (silverfish order) have high tolerance to low humidity and most of the species inhabit dry and hot environments (it's just a few that like humidity), which again makes me think that those silverfish propelled out the window will survive.
The following is multiple choice question (with options) to answer.
To survive living things | [
"need money",
"need Pu",
"need H2O",
"need hunting skills"
] | C | living things require water for survival |
OpenBookQA | OpenBookQA-1155 | rotation
Title: Are there non-rotating objects in the universe? All celestial bodies I can think of rotate. The sun, the planets, the moon, the galaxies, clusters of galaxies, the supermassive black hole at the center if the Milky Way, accretion discs, etc. It would be very strange if they didn't. They couldn't even exist.
Are there examples of non-rotating bodies? I can find no funamental reason why such an object can't exist. Maybe a planet or two stars that have had a tangential encounter. There are many objects in the universe. By chance, some will happen to have zero angular momentum. It is a meaningful question, because "all motion is relative" applies to linear motion, not acceleration or rotation.
If an object is changing rotation, slowing down and eventually spinning the other way, at some point it will have a rotation of exactly zero.
Very old black holes will shed angular momentum in the Hawking radiation, so they will naturally become non-rotating ... eventually (but not yet).
But there are objects that are very carefully given non-rotating status: scientific instruments. I suspect that Gravity Probe B was non-rotating (the whole thing, not the gyros held within), and an instrument that studies the CMB will point steadily while making an exposure.
I take back the "relative motion" part, slightly: GP-B was not rotating in the sense of there being no centrifugal forces on it, but it measured (very tiny) rotation anyway due to two GR effects. So what you mean by non-rotating can vary. All observers agree that there's no centrifugal forces; that is, no acceleration due to rotation. But it will change orientation relative to the CMB or another such object that's no in a close orbit, anyway, because space is not flat.
The following is multiple choice question (with options) to answer.
Which cannot be an example of crop rotation? | [
"planting tomatoes one year and alfalfa the next",
"planting zucchini one year and beans the next",
"planting bell peppers one year and hot peppers the next",
"planting corn one year and lelttuce the next"
] | C | crop rotation is when different crops are planted on a field in different years |
OpenBookQA | OpenBookQA-1156 | ocean, oceanography, sea-level, tides
However, I'm really curious as which are the most important amongst them? Or is it even possible to guess the tide height if I know the Lunar phase and I have a good globe with sea depth? I don't know about the size of land masses, but their distribution and the shape of ocean basins definitely play a big role.
When considering the ideal case of an all-ocean globe, i.e. one with no land masses (equilibrium tidal theory), the combined effect of sun and moon give a theoretical tidal range of less than 1 m(1). As tidal ranges can be much larger than this, there are other effects that has a greater influence.
The Bay of Fundy for example, is one of the places with the largest difference between low tide and high tide, at about 16 m. The large difference in this location has to do with the shape of the bay. The bay has a natural frequency for waves that is about the same as the frequency of the tide itself, giving an amplification of the tidal amplitude. In addition there is a funnelling effect in the inner part of the bay, giving an additional contribution.(2)
Another example of large tidal differences is the English channel, particularly the French side. In this case the tides are large at least partly because the tide moves as a coastal trapped Kelvin wave. These are waves that propagate along land, with the land to the right when looking in the direction of propagation (on the Northern hemisphere, land to the right on SH). The amplitude of the wave is highest near the coast, decaying exponentially away from the coast. As the tide in the English channel moves northward, the largest tidal range is on the French side.
With regard to guessing the tidal range, this is not entirely straight forward.
First, when discussing tides, we generally split the tidal potential into a series of oscillations having different frequencies, mainly either diurnal (period of ~24 h) or semi-diurnal (period of ~12 h).
These given frequencies are obtained through trigonometric considerations, and depend on the latitude of the point, the declination of the moon or sun relative to the equator, and the hour angle.
(The hour angle is basically the longitudinal difference between the sub-lunar point and the point we consider.)
Each of these components can vary in time and space.
The following is multiple choice question (with options) to answer.
of one misses the surf tide in the morning, will they get another chance? | [
"they have zero chance",
"they are still in luck",
"it is too late",
"all of these"
] | B | the tide cycle regularly occurs twice per day |
OpenBookQA | OpenBookQA-1157 | forces, kinematics, pressure
Now, you wish to push up on the bottom disk with all the same force as the top, and what you are basically doing right now is providing strain relief. That same force was being provided by the walls of the cylinder, which communicated it to the bolts, which communicated that force to the ground: now you are providing that force directly rather than indirectly. The walls of the piston around that lip that is holding the disc in, breathe a sigh of relief. But no new work is done on the piston if its volume changes, you have stopped before that could happen.
Suppose you keep increasing the force upwards, now what happens? Well, both of the discs start shifting upwards in the piston. If there is a similar lip on the top of the piston holding in the top disc, then when we reach that point the gas inside will compress a little more and will come to a higher pressure. If there is no such lip, then the top disc will pop off the thing and ambient air will rush in and all of the fusion gases will rush out.
The following is multiple choice question (with options) to answer.
if you push something harder, it will | [
"increase in length",
"travel less distance",
"cover more length",
"remain in place"
] | C | as force exerted on an object increases , distance travelled will increase |
OpenBookQA | OpenBookQA-1158 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
which one of these students can accurately determine the color of the board marker? | [
"a student gazing upon it",
"a student in the toilet",
"a student sitting at home",
"a student at the playground"
] | A | the color of an object can be discovered by looking at that object |
OpenBookQA | OpenBookQA-1159 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
What do some animals use to adapt to hot temperatures? | [
"perspiration",
"eating",
"fire",
"blankets"
] | A | sweat is used for adjusting to hot temperatures by some animals |
OpenBookQA | OpenBookQA-1160 | algorithms, optimization, terminology, dynamic-programming
pair<ll, pair<int, int>> combine(pair<ll, pair<int, int>> le, pair<ll, pair<int, int>> ri) {
if (le.first < ri.first) swap(le, ri);
if (ri.first == le.first) {
le.second.first = min(le.second.first, ri.second.first);
le.second.second = max(le.second.second, ri.second.second);
}
return le;
}
// Specialised range maximum segment tree
class SegTree {
private:
vector<pair<ll, pair<int, int>>> seg;
int h = 1;
pair<ll, pair<int, int>> recGet(int a, int b, int i, int le, int ri) const {
if (ri <= a || b <= le) return {-INF, {INF, -INF}};
else if (a <= le && ri <= b) return seg[i];
else return combine(recGet(a, b, 2*i, le, (le+ri)/2), recGet(a, b, 2*i+1, (le+ri)/2, ri));
}
public:
SegTree(int n) {
while(h < n) h *= 2;
seg.resize(2*h, {-INF, {INF, -INF}});
}
void set(int i, pair<ll, pair<int, int>> off) {
seg[i+h] = combine(seg[i+h], off);
for (i += h; i > 1; i /= 2) seg[i/2] = combine(seg[i], seg[i^1]);
}
pair<ll, pair<int, int>> get(int a, int b) const {
return recGet(a, b+1, 1, 0, h);
}
};
The following is multiple choice question (with options) to answer.
What is an example of combining | [
"adding H2O to water",
"pouring NaCl into salt",
"adding carbon dioxide to CO2",
"blending eggs into cake batter"
] | D | An example of combining two substances is pouring one substance into the other substance |
OpenBookQA | OpenBookQA-1161 | newtonian-mechanics, kinematics, jerk
Title: Pushing down on the gas pedal of a car a good example of jerk? I'm trying to think of the clearest examples to demonstrate the concept of jerk to a layman.
Ignoring drag and making other reasonable assumptions (friction is conveniently there to only allow you to accelerate and we assume the wheels always roll without slipping), is it reasonable to say:
A car with constant acceleration (zero jerk) would mean holding the gas pedal down at a constant displacement/angle from its starting point i.e. my foot is keeping the gas pedal held down, halfway constantly.
A car with constant jerk (thus an increasing acceleration) would mean gradually pushing down the gas pedal so its displacement/angle is increasing from its starting point at a constant rate.
I guess what I'm asking is if jerk is proportional to the distance/angle per second that the gas pedal's position is changing at? Or is there some notable amount of jounce in there too?
Pushing down on the gas pedal of a car a good example of jerk?
I'm trying to think of the clearest examples to demonstrate the concept of jerk to a layman.
Pushing down the gas pedal is not a good example of jerk.
A car with constant acceleration (zero jerk) would mean holding the gas pedal down at a constant displacement/angle from its starting point i.e. my foot is keeping the gas pedal held down, halfway constantly.
The answer is no (in an idealized case).
If you hold the gas pedal down at a constant angle then you inject a constant amount, $k*q_0$, of energy (mass of fuel per second multiplied with conversion constant $k$) in the car and in consequence the kinetic energy of the automobile at any moment of time, t, must be always equal to the total energy injected up to that moment t. Mathematically this can be written like this:
As you can see the solution is not a constant acceleration.
A car with ... an increasing acceleration would mean gradually pushing down the gas pedal so its displacement/angle is increasing from its starting point at a constant rate.
Again no.
If you press the pedal more and more as the time passes, at each moment you inject $q(t) = q_0*k*b*t$ where $b$ is a constant that depends on how fast you push the pedal. In consequence:
This time you get a constant acceleration.
The following is multiple choice question (with options) to answer.
Pushing on a pedal is an example of | [
"force",
"patching",
"practice",
"speed"
] | A | pushing on the pedals of a bike cause that bike to move |
OpenBookQA | OpenBookQA-1162 | electric-circuits, electric-current, charge, electrical-resistance, voltage
Reason 2: (This would only apply to Ohmic materials):
If we have a circuit with a constant resistance and we have zero current flow, by Ohms law how could you have a non-zero voltage?
$$V=IR$$
$$V=0R$$
$$V=0$$
Summary: I understand how one would think you can have voltage without current when you think of voltage as water pressure. My issue is I don’t think this analogy works when we look at the units of Voltage. Rather in the water analogy for electricity, it seems that water pressure would better correspond to Coulombs, since a charge will have a electrostatic force that will propagate through free space which is independent of the flow of electrons. Where voltage by its units is dependent upon displacement which would mean voltage could only be non-zero when there is electron flow. Thus an isolated net charged object in free space with no electron flow (no displacement) can not have a non-zero voltage.
My Question: Is correct to say from the above argument that you cannot have voltage without current? (Again, excluding superconductors) Yes it does make sense. Voltage is a measure of potential. When you say it has units of Joules per coulomb, that does not mean that you cannot have a potential without a charge. It simply means that were a charge to be present at that potential, then it would posses a given PE. Consider the density of gold, say, which is defined in kilograms per cubic metre. Can you say that the density of gold cannot exist as a value where there is no gold?
Likewise, Ohms law defines the voltage drop that occurs when a given current flows through a given resistor, or, conversely, the current that flows when a given resistance is used to connect two regions of differing potential where the potential difference is V. If you don't connect the two regions, you get no current, but the Voltage difference remains.
When you plug a zero current in to Ohms law to say V=0R so V=0 you are positing either a scenario in which there is no voltage (eg a flat battery), or where there is some voltage V but no current because R is infinite.
The following is multiple choice question (with options) to answer.
Electrical conduction would be when a voltage flows through | [
"a central nervous system",
"a long tree branch",
"a piece of steel wool",
"a body of water"
] | C | electrical conduction is when metals conduct electricity through metal |
OpenBookQA | OpenBookQA-1163 | waves, string, continuum-mechanics
Leissa, Arthur W., and Mohamad S. Qatu. Vibrations of continuous systems. McGraw-Hill Education, 2011.
The following is multiple choice question (with options) to answer.
Which example best shows the effect of vibration on matter? | [
"a paper airplane",
"a harpsicord",
"a pillow",
"box of candy"
] | B | as the amount that matter vibrates increases , sound produced increases |
OpenBookQA | OpenBookQA-1164 | newtonian-mechanics, momentum, everyday-life, collision
Title: Why do the pieces of breaking objects scatter? If I were to drop most objects to a level floor, they would land with a thud or bounce a few times without gaining any lateral velocity.
But a fragile object will not only break into two or more pieces, but the pieces will usually move laterally across the floor.
I suppose the center of mass of the system probably remains at the location where the object broke, but I don't see any reason for the pieces to behave any differently than a typical object that bounces or thuds. Or to put it another way, I can't determine a force that would provide the acceleration by which the pieces gained their lateral velocity.
Why does this happen? Generally, when an object collides with the floor there will be some sort of asymmetrical deformation of the object before it ultimately fails. This deformation puts a rather large amount of strain on the localized region of the object that can be considered as a sort of potential energy. When the object breaks, this energy is converted into kinetic energy, which sends part of the object flying. The part that goes flying will obviously be related to the part when the deformation caused a mechanical failure. There can, of course, be a sort of cascade of failures as well. To the degree that the system is conservative (i.e. we are ignoring things like sound waves, friction, etc.), the other pieces will tend to fly apart in a way that will conserve the linear momentum of the whole collection of parts. This gives the typical “scatter” effect that you observe.
The following is multiple choice question (with options) to answer.
When broken down, what happens to an object's shape and mass | [
"it turns to water",
"it shall be broken",
"it is then altered",
"it stays the same"
] | C | breaking down an object changes that object 's shape and mass |
OpenBookQA | OpenBookQA-1165 | botany, terminology, fruit
Title: What is the name of this part in plants, fruits, vegetables? What is the name of this part of the plant, fruit, vegetable? The thing that the plant is connected with the tree and gets nutrients with? The part we usually cut out when eat fruit.
Examples below
Papaya
Banana
Mango 'Stalk' or 'pedicel' would be an appropriate term (see, for example, this paper or this one). Specifically, you could say 'terminal part of the stalk/pedicel', though I don't know if there is a word for that.
Note that the term pedicel is commonly used for the stalk of a flower; it makes sense to use it for fruits too as they are derived from flowers.
The following is multiple choice question (with options) to answer.
Leaves are the part of a plant with the most a type of | [
"root",
"bud",
"bacteria",
"specialized compartment"
] | D | most chloroplasts are found in the leaves of a plant |
OpenBookQA | OpenBookQA-1166 | temperature, sun, light, equator, insolation
Title: Why does the intensity of sunlight depend on your latitude? People at the equator get to bask in more sunlight than Santa Clause and other inhabitants of the arctic regions. Not quite as pronounced, but they get more than me too.
Why is the sunlight more intense closer to the equator and less intense farther away from it?
When I posted this question, I was not thinking about the possible ambiguities, such as "Are you talking about the exposure across a surface area with some non-perpendicular angle to the sun," or "Are you talking about the light gathered by an optic facing the sun?" There is a difference. Since "basking in sunlight" was the example use case, let us assume exposure across a surface area which is lying on the ground. As noted in the comments, this answer applies to things like sun-bathing and solar panels, but it does not apply so much to a specific point-receptor like an eyeball. If all objects in question are pointing directly at the sun, then the angle of incidence is equal for all of them and this answer does not apply.
For an optic facing its target, the amount of atmosphere that the light passes through is a very large influencer. At higher latitudes, the sun is not directly overhead, and so the light is not coming straight down through the path of least atmosphere. Instead, it comes in at an angle, passing through more of the atmosphere before it gets to you.
For sun-bathers, solar panels, and the ground in general, the sunlight absorbed and reflected does depend very much on what is described in this answer. For that reason, more expensive solar panels are mounted on devices which alter their angle to face the sun for increased light exposure. And a sun-bather could likewise increase their exposure by mounting their platform at an angle. This is the direction the rest of the answer will take.
The answer is similar to the answer to some other questions, such as "Why does the solar power intensity change with the season?" and "Why does the solar intensity change with the height of the sun in the sky (ie: with the time of day)?"
The very short, non-technical version (tl;dr)
Each unit (think "beam of sunlight") is spread over a larger area.
That might not seem intuitive at first, but that is the answer in a nutshell. To see why, continue to the long version.
The following is multiple choice question (with options) to answer.
Which location gets the most sunlight? | [
"northern Canada",
"northern Russia",
"Brazilian rainforest",
"Sahara"
] | D | a desert environment usually has a lot of sunlight |
OpenBookQA | OpenBookQA-1167 | electricity, potential
Therefore you can appreciate that the right side of the equation is a very small number, so likewise, $V_{wire}$ must be less than a volt - and the bird experiences approximately $V_{wire}$ potential difference as well.
Does the bird experience extreme current?
Despite low voltage, high current may still be dangerous to animals. As pointed out before, the amount of current passing through the bird-wire block is $I_T=V/R_T \approx V/R_{wire}$.
At one of the bird feet, the current will split into $I_{wire}$ (which goes through the wire) and $I_{bird}$ (which goes through the bird), and then combine at the other foot. Because $V_T = V_{bird} = V_{wire}$, we can conclude that $I_{bird} = V_T/R_{bird}$ and $I_{wire} = V_T/R_{wire}$, therefore current and resistance of either component is inversely proportional:
$$ \frac{I_{bird}}{I_{wire}} = \frac{V_T/R_{bird}}{V_T/R_{wire}} = \frac{R_{wire}}{R_{bird}}$$
We previously established that $R_{wire} << R_{bird}$, so $I_{wire} >> I_{bird}$. Current must be conserved (otherwise the bird must be stealing electrons) so $I_{wire} + I_{bird} = I_T > I_{wire} >> I_{bird}$.
$I_T$ can be pretty large for the higher capacity lines, but it's not that large - it's on the order of hundreds of amperes. Even though even 0.1 A is considered lethal to humans, the bird will experience a current $I_{bird}$ which is much smaller than this.
The following is multiple choice question (with options) to answer.
When animals need to recharge, they are unable to use electricity, and therefore | [
"take naps",
"rely on fat",
"use fuel sources",
"rely on calories"
] | D | food is a source of energy for animals |
OpenBookQA | OpenBookQA-1168 | electric-circuits, potential, electrical-resistance, conductors
These analogies are not exact and are only intended to give you a better feel as to what is happening.
Hope this helps.
The following is multiple choice question (with options) to answer.
What is an example of wiring requiring an electrical conductor? | [
"a light switch turning on lights because of steel inside the wiring",
"a toasting failing because it used aluminium",
"a lightbulb burning out because of a faulty connection",
"a power outage because of an electrical storm"
] | A | wiring requires an electrical conductor |
OpenBookQA | OpenBookQA-1169 | thermodynamics, energy, home-experiment
Note 3: Peak hours tend to be during the day (this may reverse if we get wide-spread solar energy), so keeping the house cool during the day would cost even more. You pretty much have it right. We have two scenarios:
1 - Leave air conditioning on all day. Say that outside temperature is 90 degrees and inside temperature is 70 degrees. Then, all day long, the air conditioning has to remove any heat that gets into the house continuously. Heat transfer depends on the difference in temperature between outside and inside the house. In this case, heat transfer per unit time is equal to a constant K times 20 degrees. Over a whole day of D units of time, the total energy removed by the air conditioner is $20KD$ This assumes that convection (ie air draft) can be neglected.
2 - Stop the air conditioning during the day. If you stop the air conditioning, the flow of heat in the house initially will be the same. However, as time goes by, the inside temperature will increase. This will gradually reduce heat flow as it is proportional to the difference in temperatures. If the house is small enough and badly insulated, you could even get to a point where the inside temperature is equal to the outside temperature, at which point no more heat enters the house. When you get back from work, or if you have a timer a bit before, air conditioning is restarted. You now have to remove all the accumulated heat. However, since less heat entered the house over the duration of the day than if you had kept the air conditioning on, you have less work to do to cool down the house. Yes, the heat will have accumulated in insulation, furniture, walls, etc, but it doesn't matter. There is less heat total to remove.
The following is multiple choice question (with options) to answer.
Leaving coconut oil out on a counter, as the day grows hotter, what happens to the oil? | [
"changes from solid to wet",
"it hardens up a lot",
"it begins to rot",
"it needs to be refrigerated"
] | A | as temperature increases , the ability of that liquid to dissolve solids will increase |
OpenBookQA | OpenBookQA-1170 | pressure, buoyancy
Title: Is there a formula to determine if a ballon on the of deep water rises up? Imagine a balloon (again) that finds itself on the bottom of a mass deep water. The balloon is filled with air. The deep mass of water finds itself on a heavy (w.r.t. Earth) planet.
Initial, the balloon stays put (on the bottom)
After it's not stayed put anymore (it's let loose), what will happen and why?
It's clear that pressure and temperature (or other pairs of state variables) have to do with it. Maybe the water could freeze.
Is there a mathematical formula that can answer this question?
I searched and thought about the solution, but couldn't find it. But after reading the first answer it's as clear as water. The air inside the balloon is lighter than the surrounding water (if the air inside the balloon is not frozen by the high pressure, in which case I'm not sure if the ice density scales with pressure). The first answer made me realize that, so apparently, I had thought about it too little. Due to the immense pressure, the balloon will shrink in size. Once let loose, the balloon will start accelerating by quite a bit (somewhat both 2 and 3) and will eventually attain terminal velocity at a point. Then onwards, the balloon will rise at the same pace.
The following is multiple choice question (with options) to answer.
When a water balloon is frozen, it will contain | [
"a much less amount of water",
"a whole bunch of frozen ice-cream",
"the same amount of water",
"a greater amount of water"
] | C | as state of matter changes , mass will not change |
OpenBookQA | OpenBookQA-1171 | food, eggs, allergies
Title: Is it possible to be allergic to the yolk of an egg but not the egg white? At lunch one day, my friend had a hard boiled Easter egg. When he pealed it he squeezed the yolk, or yellow part, of the egg out. I asked him what on earth he was doing and he said, "I'm allergic to the yellow part of the egg not the white." I was very confused by this, he also sad he was allergic to tomatoes but could still eat pizza with sauce on it, apples but only the skins, and some other strange things. I didn't think this was possible at all. Can anyone explain this and tell me if it's even possible to be allergic to one part of an egg and not the other, or is it all in his head. If this is possible, is there an actual name for this condition? The protein composition of the egg white and egg yolk differ appreciably. Hence, it is plausible for one to countenance symptoms of indigestion when consuming the egg yolk as opposed to the albumen, egg whites. It is important to stress that your friend may only an indigestion towards egg yolks as opposed to an immune response to an antigen.
If we consider the protein family, the egg yolk comprises a family of phosvitins, a group of highly phosphorylated proteins capable of mustering iron and calcium metal cations - serving a role in embryo development.
These are primarily absent from the albumen which comprises (with an unexpected name!) a highest percentage of suspended ovalbumin, ovotransferrin and ovomucoid. As demonstrated by the American College of Allergy, Asthma & Immunology, it is feasible to suffer an intolerance towards the egg yolk and yet suffer no gastro-enteric indigestion to the egg whites.
More information regarding the American College is available from: https://acaai.org/allergies/types/food-allergies/types-food-allergy/egg-allergy
The following is multiple choice question (with options) to answer.
Where might you find eggs? | [
"forest",
"space",
"lava",
"ocean"
] | A | some birds live in forests |
OpenBookQA | OpenBookQA-1172 | humidity, air-pollution
Title: Does usual city pollution have effects on relative humidity? I've noticed that in a rural area with low pollution the relative humidity is constantly lower than the humidity in a high polluted city. Is there any correlation between pollution and humidity? By way of reference, "humidity depends on water vaporization and condensation, which, in turn, mainly depends on temperature".
From the information you have supplied in your comments. There are waters in Bucharest and forests in the suburbs, but no waters or forests where the country house is located.
From your information, Bucharest has a number of sources of atmospheric water vapour, the river that flows through it (evaporation of water) and the forests in the suburbs (transpiration of water). Additionally, motor vehicle exhausts will increase the humidity as water vapour is one of the products of the combustion of hydrocarbons.
The warmer the air, the greater its capacity to hold moisture. Cities tend to be warmer than rural areas due to the heat island effect, which is the result of modifying land surfaces and the generation of waste heat.
Humidity in the rural location will arise from evaporation of water in the soil and transpiration from crops or grasses. Such transpiration will produce less water vapour than forests. Additionally, the rural location will have significantly fewer cars producing water vapour in their exhausts. Consequently, the rural location will be less humid than the city.
The reason why Bucharest is more humid that the rural location has more to do with the greater availability and vaporization of water in Bucharest and the temperature of Bucharest than the amount of pollution in Bucharest.
The following is multiple choice question (with options) to answer.
What is more likely to have caused pollution in the air? | [
"it developed on its own",
"a hurricane",
"an action by a business",
"a flock of birds"
] | C | humans cause pollution |
OpenBookQA | OpenBookQA-1173 | temperature, light, heat
Title: Why does sunburn cause fever? Today I found out that sunburns can cause fever.
What I don't understand is how/why? In my understanding fever is the side effect of an immune reaction against an intruder, mainly bacteria (though I admit I can be wrong).
Google searches like "can sunburn cause fever" only bring up that it is possible, but not why. Here is a good article on the topic.
https://www.nlm.nih.gov/medlineplus/ency/article/003227.htm
But it's most likely due to the fact that a sun burn is an actual burn on the skin that can cause inflammation, inflammation can in turn cause fever. Also having a really bad sunburn can open you up more to the possibilities of skin infections. If this happens then once again you might get a fever due to infection. If you really want to find out more on the cause of fever after sunburn you need to examine the pathophysiology of fever and why fever happens. I bet my money on fever due to skin inflammation after a sunburn, I guess the real question would be why does inflammation cause fever since sunburn = skin inflammation
Here is a good article
http://antranik.org/inflammation-and-the-pathophysiology-of-fever/
The following is multiple choice question (with options) to answer.
A sunburn is most likely to happen after hiking in a | [
"desert",
"forest",
"wetland",
"jungle"
] | A | a desert environment usually has a lot of sunlight |
OpenBookQA | OpenBookQA-1174 | mechanical-engineering, gears
Hopefully this all makes sense so far.
A lever doesn't actually move strictly up-and-down, though. It rotates about the fulcrum. The actual distance the input traverses is $L_1\theta$, and the output moves $L_2\theta$, where $L_1$ is the length of the lever from the input side to the fulcrum, $L_2$ is the length of the lever from the output side to the fulcrum, and $\theta$ is the angle of how much the lever rotated.
Define the arc length, or distance actually traveled by the input or output end of the lever to be $s$. The input moves:
$$
s_1 = L_1\theta \\
$$
The output moves:
$$
s_2 = L_2\theta \\
$$
If you divide the output by the input, you can see that:
$$
\frac{s_2}{s_1} = \frac{L_2\theta}{L_1\theta} \\
$$
The thetas cancel, and you're left with:
$$
\frac{s_2}{s_1} = \frac{L_2}{L_1} \\
$$
which can be restated as:
$$
\boxed{s_2 = \left(\frac{L_2}{L_1}\right)s_1} \\
$$
The output distance traveled is equal to the input distance times the ratio of lever arm lengths. You can plug this back into the work equation:
$$
F_1 s_1 = F_2 s_2 \\
F_1 s_1 = F_2 \left(\frac{L_2}{L_1}\right)s_1 \\
$$
Cancel the $s_1$:
$$
F_1 = \left(\frac{L_2}{L_1}\right)F_2 \\
\boxed{F_2 = \left(\frac{L_1}{L_2}\right)F_1} \\
$$
The following is multiple choice question (with options) to answer.
A lever is used to move objects that are | [
"hefty",
"light",
"short",
"round"
] | A | a lever is used for moving heavy objects |
OpenBookQA | OpenBookQA-1175 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A boy might have brown hair due to | [
"inheritance",
"luck",
"magic",
"fire"
] | A | the colors of the parts of an organism are inherited characteristics |
OpenBookQA | OpenBookQA-1176 | botany, species-identification
Title: Plant identification? Can anyone identify the plant below? It's in a backyard in Pennsylvania, and the photo was taken today. Those flowers don't come from the same plant as that big leaf in the front do they? Cant help you with the leaves, but the flower looks like a daylily. source: I know nothing about plants, but happen to have a mom who got a degree in horticulture :)
The following is multiple choice question (with options) to answer.
A specific plant is found | [
"in some areas",
"in outer space",
"nowhere",
"in all areas"
] | A | a plant requires a specific climate to grow and survive |
OpenBookQA | OpenBookQA-1177 | botany
Title: Do any plants exhibit hormonal changes similar to puberty? Just what the title states.
Are there any plants/trees that exhibit a growth spurt at a definite interval after the shoot appears? In flowering plants (the angiosperms) there are several developmental transitions in the life of the plant. I won't list the plants, because the list includes pretty much all of them (although the magnitude in the change of developmental pace differs widely between taxa and environments).
First there is seed germination, which is controlled hormonally. Absence of germination is usually imposed by abscisic acid, whilst germination is caused at the appropriate time by gibberellic acid and ethylene (among other things; Holdsworth, Bentsink & Soppe, 2008).
Next, in many herbaceous species there is a transition between a spreading growth stage (e.g. rosette growth) and the flowering stage. The 'growth spurt' here is the differentiation and elongation of the flowering stem, and then subsequently the sudden flowering of buds. The transition is also controlled hormonally, by a variety of hormones including auxin (Zhao, 2010), gibberellic acid, ethylene (Schaller, 2012), and the long anticipated, recently confirmed florigen (Choi, 2012). Ethylene and abscisic acid then play important roles in the next developmental transition when seeds and fruits are produced and dehisced.
Small RNAs are also now being revealed to play a large role in controlling the timing of developmental, but they are upstream of the hormonal changes. In particular some key miRNAs are involved in auxin-based regulation of branching, and in embryogenesis (Nodine & Bartel, 2010), and RNA silencing is involved in the switch from rosette growth to flowering growth (reviewed in Poethig, 2009 and Baurle & Dean 2006).
The following is multiple choice question (with options) to answer.
What does girth in a flower do? | [
"makes it smell better",
"makes it more beautiful",
"decreases the stigma size",
"increases the pollenator amount"
] | D | as the size of a flower increases , the number of pollinators it will attract increases |
OpenBookQA | OpenBookQA-1178 | meteorology, lightning, extreme-weather
Title: Should I worry about copper pipe outside attracting lightning strikes? I used some copper pipe outside to string some decorative lights up higher in my yard. I used the copper because I thought it would be pretty and patina nice.
Then I remembered that copper is a good conductor, and there's a lightning storm outside. Should I be concerned about attracting lightning strikes? It's not grounded. Any build up of static electricity in the ground will seek to connect with opposite charge in a storm cloud, and will spark through the line of least resistance. Any high metal structure, whether it is copper or not, is a candidate for the line of least electrical resistance. You may be able to protect your copper support by a higher lightning conductor (sharp spikey, high, pointing up, and well earthed, preferably to the local water table). Also bear in mind that the lightning can jump over short distances possibly to your copper support.
I once observed a lightning strike on a house close to where I live in South Australia. The lightning hit a TV aerial, jumped to the metal guttering around the roof, jumped to metal window frames, and made contact with the house's internal wiring. It was like a bomb had gone off. Every electrical appliance that was plugged in was fried. The guttering kind of exploded, and a sour smell of 'charred house' lingered for weeks.
So yes, you should be concerned!
The following is multiple choice question (with options) to answer.
if a bad wiring affected a living room floor, which of these would be safest to climb? | [
"the mahogany desk",
"the metal chair",
"the steel lamp",
"the ceramic floor"
] | A | wood is an electrical energy insulator |
OpenBookQA | OpenBookQA-1179 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
What is an example of the fact that crop rotation renews the soil? | [
"planting rows of carrots and peas next to one another",
"planting peas one season then carrots the next",
"planting a field of corn with different types in it",
"tilling the soil in between crops"
] | B | crop rotation renews soil |
OpenBookQA | OpenBookQA-1180 | Hey, thanks for your help guys. For a minute there, I thought that this theoretical person could not safely expect to live to be 82 years old.
9. Jun 16, 2012
### SW VandeCarr
In fact, on a purely probabilistic basis, for any finite time no matter how large, there is a non zero probability that a person would survive that long. So for a sufficiently large population, there would be a theoretic person that would live 100,000 years. This, of course, has no basis in biology.
In terms of the probability of being murdered, the model would not hold for the 100,000 year old person. In terms of the model, probably the best one can do is assume the proportion of causes of death would be constant. The calculation above needs to be corrected for overall survival in terms of death from any cause.
Last edited: Jun 16, 2012
10. Jun 16, 2012
### viraltux
Interesting... but 0.37% is not that small percentage, don't you think? That means, roughly speaking, that a community of around 300 persons can expect that one of them will be murdered.
If you consider that the number of people we know plus acquaintances can easily be around 300 persons that would mean that most 82 year old persons know of someone in their circles who has been murdered. Mmm... that might be an interesting survey.
11. Jun 16, 2012
### SW VandeCarr
As I said in my previous post, this is a misapplication of statistics. You have to consider survival in terms of all cause death. If you just consider the murder rate, then at some point nearly everyone gets murdered.
12. Jun 16, 2012
### moonman239
I know that.
This person will not die until he reaches age 82, if he is not murdered. As mentioned before, this person has a 68% chance of living to be 82.
13. Jun 16, 2012
### D H
Staff Emeritus
The probability of living to 82 per this problem is 99.63%, not 68%. You missed the decimal point on the 0.37%.
14. Jun 16, 2012
### SW VandeCarr
The following is multiple choice question (with options) to answer.
When the old man was much younger, he still had | [
"brown eyes",
"baldness",
"gray hair",
"wrinkled skin"
] | A | eye color is an inherited characteristic |
OpenBookQA | OpenBookQA-1181 | mountains, geography, paleogeography, isostasy, mountain-building
Title: What were the tallest mountain ranges in Earth's geological past? There have been numerous episodes of mountain building in Earth's geological history, particularly through the super-continent cycle. Many mountains and mountain ranges have been eroded, as mentioned in the similar question Determining the paleoelevation of mountain ranges.
What are believed to be the tallest mountain ranges in Earth's geological past? Additionally, what evidence is there to support these palaeoelevations? Factors determining the maximum possible height of mountains include the rate of uplift versus the rate of erosion[a] and rock strength.
Rock strength is controlled by the type and internal structure of the rock in question. There is some evidence that once mountains extend above the snow line, glacial and periglacial erosion have a stronger control than exhumation/uplift rate (Brozovic et al, 1997; Egholm et al, 2009).
Everest and the Himalaya have reached their maximum possible elevation: the formation of the Tibetan plateau is due to the failure of rocks preventing the maintenance of discrete mountain peaks. The principle of uniformitarianism suggests that - subject to differences in variables discussed by Egholm et al, including crustal composition - the Himalaya and Tibetan plateau are an excellent approximation to the maximum achievable height of mountain ranges. However, identifying which specific palaeoranges were tallest (as opposed to calculating a plausible upper limit on height) is a significantly harder problem to solve.
[a] Though note that the rate of erosion increases as the rate of uplift increases - for more on erosional equilibrium, see e.g. Riebe et al (2000).
The following is multiple choice question (with options) to answer.
The Appalachians reach amazing heights because of how stone | [
"blew up",
"piles together",
"melted lava",
"created anchors"
] | B | the Appalachians were formed by rock folding |
OpenBookQA | OpenBookQA-1182 | zoology, ethology, behaviour, psychology, death
I can't prove it to you, but I know that my Beagle had a rich emotional life. I know this because I spent huge amounts of time with him. He was a close friend of mine. I would just as soon question whether my wife has real emotions as my dog. I can't prove that my wife's emotions are real either, but I don't have to. It would be silly to assume that everything she shares with me is some sort of evolutionary programming, and not real emotion. Now, when I extend this to cetaceans, I must admit that I don't have any friends in those circles. So I can only guess.
The following is multiple choice question (with options) to answer.
An animal can do some essential things without being taught or ever seeing it done | [
"we are unaware",
"that is negative",
"that is affirmative",
"all of these"
] | C | an animal knows how to do instinctive behaviors when it is born |
OpenBookQA | OpenBookQA-1183 | # Thread: physics tourist & bear problem
1. ## physics tourist & bear problem
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
2. Originally Posted by rcmango
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
The maximum value of d is such that the bear gets to the car at the same time the tourist does.
So set up a coordinate system such that the bear is at the origin and positive x is in the direction from the bear to the tourist.
Both are moving at a constant speed. The bear has to cover 27 + d meters in the same time the tourist covers d meters.
So for the tourist:
[tex]d = v_t t = 3.5t[tex]
Thus
$t = \frac{d}{3.5}$
For the bear:
$27 + d = v_b t = 6 \left ( \frac{d}{3.5} \right )$
Now solve for d.
-Dan
3. Hello, rcmango!
Another approach . . .
A tourist being chased by an angry bear is running in a straight line
toward his car at a speed of 3.5 m/s. .The car is a distance $d$ meters away.
The bear is 27 meters behind the tourist and running at 6.0 m/s.
The tourist reaches the car safely.
What is the maximum possible value for $d$?
The tourist has a 27-meter headstart.
Relative to the tourist, the bear has a speed of 2.5 m/s.
To cover 27 meters, it takes the bear: . $\frac{27}{2.5} \:=\:10.8$ seconds.
The following is multiple choice question (with options) to answer.
A bear's blubber | [
"enables him to keep his body cozy",
"enables him to eat more",
"is useless and a burden to his health",
"makes it more difficult for the bear to function"
] | A | fat is used to keep animals warm |
OpenBookQA | OpenBookQA-1184 | thermodynamics, physical-chemistry, combustion
Title: Is there an 'intuitive' explanation for "Which burns more?" In helping a friend's son with his grade 10 science homework, I came across a question that essentially asked the following:
"If two objects of equal mass but different specific heat capacities are touched, which will burn more?"
The wording of the question implied that this was meant to be a thought experiment rather than anything calculation-based.
My first reaction was that this question was probably quite a bit more complex than it was made out to be; a quick search online and on this site confirms this, however ideas like conductivity (which I'm familiar with), diffusivity & effusivity (which I'm not) and others are well beyond the student's understanding at the moment. I also felt "burn more" was rather vague.
To address these concerns, I made the following two assumptions:
since the question made no reference to time, I took the phrase "burn more" to mean "transfer the most energy by the time equilibrium has been reached"
all parameters like mass (mentioned in the question), density, conductivity, area of contact, etc., other than specific heat capacity and time would be equal.
The following is multiple choice question (with options) to answer.
What would burn more quickly? | [
"wet log",
"green leaves",
"soggy tree trunk",
"sun dried branches"
] | D | dry wood easily burns |
OpenBookQA | OpenBookQA-1185 | inorganic-chemistry, acid-base, everyday-chemistry
$$\ce{H2O + CO2(aq) <=> H2CO3}$$
and the protolysis of true $\ce{H2CO3}$
$$\ce{H2CO3 <=> H+ + HCO3-}$$
For a weak acid
$$\begin{align}
\log[\ce{H+}]&\approx\frac12\left(\log K_\mathrm a+\log[\ce{H2CO3^*}]\right)\\
&=\frac12\left(-6.3-5.0\right)\\
&=-5.65\\
\mathrm{pH}&=5.65
\end{align}$$
Thus, pure rain in equilibrium with the atmosphere has about $\mathrm{pH}=5.65$. Any acid rain with lower $\mathrm{pH}$ would be caused by additional acids.
The following is multiple choice question (with options) to answer.
If it starts raining acid rain you should | [
"Go for a quick run",
"Move the car to the garage",
"Go dancing in the rain",
"Go for a bike ride"
] | B | acid rain has a negative impact on water quality |
OpenBookQA | OpenBookQA-1186 | species-identification, botany
Title: Can you identify this (possibly waterstoring) plant? My son brought home a sapling, and after 4 years in a pot it is now about 30 cm or a foot high (from the "ground" to the top of the "stem"). It doesn't need a lot of water and can go weeks without being watered, in fact it seems to me as if it is storing water in the thicker upper part of its stem. When I water it "too much", new leaves start to grow. There are tiny "blossoms" along the stem, and every now and then small, dark brown, spherical seeds about 2 mm in diameter pop out from the "blossom" and are thrown across the room as far as a meter (about a yard) or two.
What plant is this?
I believe that it is not native to my European home but some kind of decorative plant imported and sold through a florist or imported privately, but I'm not sure. It is an Euphorbia leuconeura (Madagascar Jewel), which is native to Madagaskar. The leaves and the thick (waterstoring) stem with a narrow base is very typical.
The plant is cool in the sense that it easily produces seeds (also as potted) which it can shoot away from the plant. I've had it myself and you can sometimes hear seeds hitting the window or floor. Even if it is easy to grow and to reproduce it is actually considered threatened in its native habitat (IUCN Red-listed as Vulnerable) due to habitat loss
The flowers are very small and found directly on the stem, see below:
(picture from Wikipedia)
The following is multiple choice question (with options) to answer.
An indian hawthorn that has received more water will usually be | [
"taller",
"older",
"less healthy",
"colder"
] | A | as the amount of water received by a plant increases , that plant will usually grow |
OpenBookQA | OpenBookQA-1187 | meteorology, clouds, weather-satellites
Title: Great Lakes - cookie cutter clouds On 2014-07-10, in the afternoon, the GOES East satellite image in the visible showed a mass of cloud in central North America. However, in the middle, the Great Lakes stood out in a most extraordinary way, since they were almost completely free of cloud. It was like a cookie-cutter. The cloud followed the outline of the lakes precisely. Why is that?
Here is a second view, from MODIS data: MODIS image of the Great Lakes There are a couple reasons for this. First, Lake Michigan is still cold this time of year, relative to the land that surrounds it. Warm air flowing over the lake will exchange heat and cool, reducing its buoyancy, which will alter the heights at which clouds will form and inhibit lift for surface parcels to achieve that height.
That helps explain the cloudlessness over the lake, but this extends a bit inland as well. I'd have to do a little digging to verify this, but just from that image it looks like that demarcation of cloud/no cloud around the lake is a sea breeze front (or in this case, a lake breeze). The daytime lake breeze flows inland from the water, rises over land and then flows back to the lake where it descends. This will promote clouds where the circulation rises and inhibit them where the circulation falls.
There may also be an orographic effect on along the northern portion of western MI shore, as there are large sand dunes and hills in that area. The upslope flow could be the reason the clouds hug that shore a bit closer than other regions around the lake.
In summary, that looks like a really well defined lake breeze circulation, which explains the shape and location of the clouds.
The following is multiple choice question (with options) to answer.
Grey clouds are a source of | [
"hot weather",
"electrical currents",
"falling liquids",
"vitamin D"
] | C | grey clouds are a source of precipitation |
OpenBookQA | OpenBookQA-1188 | evolution, dna, natural-selection
It seems plausible to me that we (advanced life) could have a biological mechanism to "write" needed alterations into either our own DNA or our reproductive DNA over time, triggering the very specific evolutionary developments necessary to our survival without relying on random mutation.
My question:
Is this possible? Does any similar mechanism exist that we know of? If not, how can so many specific (advanced) evolutionary leaps be otherwise explained? This entire answer will be long, so read the short part first, then read the rest if you (or anyone else) is curious. Citations are included in the long section. I can include additional citations in the short section if needed.
Long Story Short
Your question touches on some common misconceptions about how the evolutionary process. Organisms don't "want" to evolve traits. Traits evolve through the biological processes of random mutation and natural selection.
Organisms do not "want" to evolve traits. (Well, OK, I'd love to evolve an extra pair of hands but that is not possible.) Natural selection works by modifying existing traits. Your turtle can stare all she wants at food out of reach but she will not evolve a longer neck. Instead, natural variation exists among neck lengths of the turtles because of variation of the genes that determine features related to overall boxy size. Those individuals with longer necks may be able to get a bit more food, live a little longer, and reproduce a little more. They will pass along their genes to their offspring, so perhaps more of their offspring will also have longer necks. Over many generations, the turtles may have somewhat longer necks.
A common misconception is that the traits of organisms are precisely adapted for a specific need. They are not, for a few reasons. First, natural selection occurs relative to the current environment. Adaptations that work well in one environment may not be so useful in another environment. Environments are rarely stable over evolutionary time so traits are subject to constant change.
Next, as mentioned above, natural selection can only work on what traits are present. While an extra set of arms would be handy, I am a tetrapod. My four appendages, along with the appendages of all other tetrapods, trace back to our common ancestor. The appendages of all tetrapods are modifications of that ancestral trait.
The following is multiple choice question (with options) to answer.
Which traits could be pass along using reproduction and genetic material? | [
"nose",
"thoughts",
"money",
"habits."
] | A | reproduction is when an organism passes genetic information from itself to its offspring |
OpenBookQA | OpenBookQA-1189 | zoology, pathology, herpetology
Title: How do pet gecko lizards pose a health risk? Does having gecko lizards living in your house pose any health risk? If you're referring to keeping geckos as pets, like all reptiles, amphibians and birds, they come with a small but finite risk of contracting salmonellosis. Having said this, the infection is easy to avoid if you maintain basic hygiene.
On a personal note, I know dozens (perhaps hundreds) of people who keep or have kept reptiles as pets and have yet to meet anyone who contracted salmonellosis. Basically, if you wash your hands after touching the gecko, keep it away from food preparation areas and don't put the lizard in your mouth, you should be fine.
If you're talking about geckos living free in your home, as is common in many tropical places, I have never heard of any health risks associated with them. If anything, I would think that the geckos would reduce health risks by eating insects such as cockroaches and mosquitoes that are prominent disease carriers.
The following is multiple choice question (with options) to answer.
Some lizards can live in | [
"environments lacking oxygen",
"moisture deficient environments",
"zero gravity environments",
"food barren environments"
] | B | some lizards live in desert habitats |
OpenBookQA | OpenBookQA-1190 | zoology, ethology, sociality
Canfield, J., Hansen, M. V., Becker, M., & Kline, C. (1998). Chicken Soup for the Pet Lover’s Soul. Deerfield Beach, FL: Health.
The following is multiple choice question (with options) to answer.
What are sources of shelter for small animals? | [
"andesite",
"wind",
"sun",
"air"
] | A | rocks are a source of shelter for small animals in an environment |
OpenBookQA | OpenBookQA-1191 | solutions
(source: Hashimoto et al. in Molecules 2019, 24, 2296 (doi.org/10.3390/molecules24122296), section 3.2; open access publication.)
This pattern is seen for inorganic reagents like $\ce{HCl}$ dissolved in water, yet equally available in methanol, 1,4-dioxane, etc. (example); and organometallic reagents, e.g. butyllithium, methylmagnesium bromide.
The following is multiple choice question (with options) to answer.
An example of a reusable product is | [
"a plastic cup",
"a soda can",
"a steel cup",
"a trash bag"
] | C | something reusable can be used more than once |
OpenBookQA | OpenBookQA-1192 | classical-mechanics, experimental-physics, home-experiment
Title: Can force be transferred through objects in a chain to the last object without any displacement of objects in the middle?
sorry for terrible graphical representation, I did an experiment, i took 6 coins fixed 4 of them in one place by placing some real heavy objects on them , then i took a 5th coin placed it in the final position at the last , all these coins were touching each other and only the fifth one was free to move .
Now i took a striker (6th coin) and collided it with this chain of coins and every time the final coin moved as if the force was transmitted through all these coins in the middle to the last one while themselves NOT(assumption) moving at all . How can this happen how can the force be transmitted to the final coin if the coins in the middle didn't moved at all the experiment works with as much as 10 fixed coins in place of 4 . By far the only explanation i can give is that the coins in the middle do move(very little ) but cant prove this theory . This is similar, but not quite identical to Newton's cradle, with the difference being the heavy objects placed on the middle coins.
To explain things, first consider the simpler case where there is no heavy object on top of the coins, and suppose the 5 nonmoving coins in "frame 1" are separated by a distance $L$.
When two objects of mass $m$ and velocities $v_1$ and $v_2=0$ undergo a perfectly elastic collision, there is no energy loss to heat, and so solving energy and momentum conservation $\frac{1}{2}m_1 v_1^2+0=\frac{1}{2} m_1 {v'_1}^2+\frac{1}{2}m_2 {v'_2}^2$ and $m_1 v_1+0=m_1 v'_1+m_2 v'_2$ for the final velocities $v'_1$ and $v'_2$ yield
$$v'_1=0 \mbox{ and }v'_2=v_1.$$
The following is multiple choice question (with options) to answer.
Moving heavy objects | [
"requires more might",
"requires little strength",
"should be easy",
"should be avoided"
] | A | as the mass of an object increases , the force required to push that object will increase |
OpenBookQA | OpenBookQA-1193 | physical-chemistry
Title: Which is hardest: iron, brass or bone? I was hopping around random wikipedia articles when I came across the article for the Behemoth. In the description for the beast it says:
His bones are as strong pieces of brass; his bones are like bars of
iron
So it got me thinking, which of these three substances is hardest: iron, brass or bone?
(I had a quick look at the Mohs scale, which lists iron as 4, but could not find anything for brass or bone.) These two sources both put bone at a hardness of 5:
http://www.chacha.com/question/how-hard-is-bone-according-to-moh's-hardness-scale
https://answers.yahoo.com/question/index?qid=20110310200841AABwtMj
Whether they are trustworthy is questionable though, so take it as you will.
This source put brass at 3 and iron at 4.5:
http://www.jewelrynotes.com/the-mohs-scale-of-hardness-for-metals-why-it-is-important/
and this image puts brass at 4 and iron at 4-5 (Similar to 4.5):
http://patentimages.storage.googleapis.com/WO2001048807A1/imgf000009_0001.png
While these different sources seem to have conflicting data, I think it would be safe to assume that Brass is the softest of these three materials, Iron comes second, and Bone is the hardest.
Edit: In the description of that monster, the adjective used is 'strong'. You may want to consider how much force each of these materials can withstand instead of how hard they each are :)
The following is multiple choice question (with options) to answer.
Which rock is a fingernail harder than? | [
"Copper",
"Graphite",
"Calcite",
"Quartz"
] | B | measuring the hardness of minerals requires scratching those materials |
OpenBookQA | OpenBookQA-1194 | time
With respect to the Sun, the Earth rotates once every 24 hours. But because the Sun's apparent position changes in the sky due to Earth's revolution around the Sun, the Earth rotates once every 23 hours, 56 minutes, 4 seconds with respect to the stars. Because of this 3 minutes, 56 seconds difference, all stars rise and set 3 minutes, 56 seconds earlier each succeeding day. This applies to the time of a star passing through the meridian as well.
So, on the next day, April 29, Arcturus will pass the meridian at 22:56:04.
And what day does the Arcturus will pass the meridian about 01:00:00?
Over the course of an entire year, about 365 days and 6 hours, these 3 minutes and 56 seconds adds up to an entire day, so that exactly one year later, the same star will pass through the meridian at the same time of day.
For Arcturus to pass the meridian exactly 22 hours earlier, it should be 22/24 of a year before then, or about 335 days later, or about 30 days earlier, or March 29.
solar time equal sidereal time minus 12hr
Generally not correct. Solar time is based on the average time it takes for the sun to cross the meridian (24 hours), and sidereal time is based on the time it takes for a star to cross the meridian. Sidereal time counts 24 "hours" in 23 hours, 56 minutes, and 4 seconds, meaning that it runs slightly faster than our normal solar time.
There is one day in which solar and sidereal time are 12 hours off, on the northward equinox in March. The Sun is on the northward equinox, but solar time is measured since midnight where sidereal time is measured since passing the meridian (local noon).
There is one day in which solar and sidereal time coincide, on the southward equinox in September. The Sun is on the southward equinox, 180 degrees in the sky from the northward equinox, so the 12 hours off from midnight and the Sun being 12 hours off from the northward equinox cancel.
The following is multiple choice question (with options) to answer.
The back and forth on daily routine in the sky happens how often? | [
"one time during the single rotation",
"one cycle of the sun",
"during the winter solstice",
"springtime when the moon is at apex"
] | A | cycles of day and night occur once per day |
OpenBookQA | OpenBookQA-1195 | organic-chemistry, boiling-point
Title: At what temperature will proteins and fats boil in a vacuum? A question was asked on another stackexchange site:
This is not nice perspective, but eventually it will happen. An astronaut falls out of spaceship because of damage caused by collision with other object, or because of suit decontamination. The fluids from the body would evaporate, and if any bacteria would survive, than only as spores. Does it mean the perfect mummification of the body? Or there will be some decay, caused by enzymes from damaged cells, for example?
Given that the water in the body will outgass taking with it much of the rest of the body, are there any cited sources that specify the pressure at which proteins, fats and bones will break down and become vapour? You're talking about the human body being exposed to outer space and asking about what would happen to it's internal structure. Bones, fats and proteins are within the enclosed system that is the human body, they are not subjected to the low pressures of space. The answer to the pressure at which proteins, fats and bones will break down and become vapour is not related to the answer to what would happen to them in the human body if the body is exposed to the vacuum of space. Nevertheless, I'll try to provide both answers.
The answer to the second question (short-term) can be found on NASA's website at "ask an astrophysicist". It's actually quite surprising for someone used to sci-fi movies:
You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.
The following is multiple choice question (with options) to answer.
What is an example of if an organism becomes too hot then that organism may die? | [
"a dog panting under the hot sun",
"a bear shedding fur to cool off",
"an earthworm drying up on a sidewalk",
"a bird stopping to rest after a long flight"
] | C | if an organism becomes too hot then that organism may die |
OpenBookQA | OpenBookQA-1196 | atmosphere, ocean, hydrology, climate-change
Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.
Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.
Waves come about from wind, so they're a twice-indirect form of solar power.
Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.
How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of about 1400 Watts per square metre. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.
So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$
The following is multiple choice question (with options) to answer.
Water, while a finite resource, is renewable because | [
"water is good to drink",
"water is hard to dry up",
"water is quite cyclical",
"water is found in trees"
] | C | water is a renewable resource |
OpenBookQA | OpenBookQA-1197 | botany, plant-physiology, plant-anatomy
Title: How do plants grow year after year even though they die? How do plants grow, die, and then grow again? For instance, when my plants die during the winter, how do they grow again next year? Does it have something to do with the root system? Or do they even die? It depends on the type of plant, but basically not all of the plant dies. Plants have evolved a number of strategies for winter* dormancy. These are common ones, but probably not an exhaustive list.
Deciduous trees and bushes simply drop their leaves in the fall, and so may look "dead" to the unskilled eye - though with practice, it's usually easy to distinguish between dead and dormant. Then when the weather warms in the spring, new leaves grow.
Other perennial plants may lose some or all of their top growth, even dying back to ground level, but the roots will be alive, and will start growing when the ground warms.
Still other plants have developed specialized underground structures like bulbs & rhizomes - think daffodils, tulips, irises, and similar. The rest of the plant dies, only to grow again from the bulb when conditions are right.
It's worth noting that most, if not all, of these are used for propagation as well, often naturally, and frequently with a bit of human help. Bulbs and rhizomes multiply: the daffodil bulb you planted a few years ago may now be a dozen bulbs, each of which can be moved to grow new ones. Many perennials can be increased by dividing the root mass into pieces, each of which will become a new plant. And cuttings from many trees & bushes can be induced to form new root systems, and become new plants.
Or summer, dry season, &c. For simplicity, I'll just say "winter".
The following is multiple choice question (with options) to answer.
Flowers start die when | [
"They are pulled from the ground",
"They are sung too",
"They are given water",
"They have lots of sunlight"
] | A | decomposition is when a decomposer breaks down dead organisms |
OpenBookQA | OpenBookQA-1198 | energy-conservation, acoustics, material-science, dissipation
For a more detailed explanation, every material has a unique speed of sound which depends on its Young's modulus $Y$ (for solids) or equivalently on its bulk modulus $\beta$ for fluids. First consider the metal itself. It's Young's modulus is given by
$$ Y = \frac{\rm stress}{\rm strain} = \frac{F/A}{\Delta L/L}. $$
By counting the molecules and making connections between the macro- and micro- level behaviors, you can derive the equivalent expression* for the modulus
$$ Y = \frac{k_{\rm s,i}}{d}. $$
Here we model each atom as a "ball" of diameter $d$, each ball connected to each other with a spring of interatomic stiffness $k_{\rm s,i}$. When you hit the metal, you give some atoms a particular stretch $x$, and thus from Hooke's law with damping factor $2b$
$$ m_{\rm atom} \ddot x = -k_{\rm s,i}x - 2b\dot x, $$
which gives the decaying solution
$$ x(t) = Ae^{-bt}\sin\left(\omega t + \phi\right),$$
where $\phi$ is some phase angle and $\omega^2 = {\frac{k}{m}} + b^2$ is the atom's angular frequency.
Then, the speed of sound in the metal is given by
$$ v_s = \sqrt{\frac{Y}{\rho_m}}, $$
where $\rho_m$ is the density of the metal. Sound is a longitudinal wave, meaning its oscillation is in the same direction as its motion. See the below gif.
The following is multiple choice question (with options) to answer.
which of these apply to the values of matter vibration and sound given off? | [
"both values are inversely proportional",
"both values have direct proportionality",
"both values are unrelated",
"none of these"
] | B | as the amount that matter vibrates increases , sound produced increases |
OpenBookQA | OpenBookQA-1199 | earth-rotation, geologic-layers
Title: Do Earth's layers move at different speeds? I don't have a background in Geology but this question popped in my head the other day and can't find an answer anywhere else.
If I remember science class correctly, Earth's layers have different element compositions. Would it be correct to assume that they have different densities and different frictions as a result? And if they do, does it follow from it that they rotate at different speeds?
Thanks. Im am currently doing my masters in geophysics (last semester) and before that I did a bachelor in geoscience.
I assume by layers you mean the crust, the mantle and the core.
These all have different composition and also different densities. But the earth rotates as a whole, not the individual layers, all layers have the same angular velocity. That means they all make one rotation per day.
These layers are also not the perfect boundaries we like to imagine, but more a change in properties around a finite depth. This depth can even change at different places.
The following is multiple choice question (with options) to answer.
The mantle is a layer of the Earth; what is something other than a layer? | [
"crust",
"inner core",
"outer core",
"lava pit"
] | D | the mantle is a layer of the Earth |
OpenBookQA | OpenBookQA-1200 | rotation
Title: Cycles that are longer than the year, but less than 1000 years Wondering what primary astronomical cycles there are that are greater than a year (which is a cycle around the sun), but less than 1000 years-ish (on that scale). There is the cycle of the moon phases too, and the cycle of the earth making a full rotation (a day). But I wonder if there are any cycles at a bigger-than-a-year scale, but not too big. I guess there's also the cycle of a stars life (but that is kind of a big scale, on the order of billions of years), but I am more wondering in terms of rotation what sort of cycles there are. I guess there is another one, Axial Precession, but that is a bit large such as on the order of tens of thousands of years. Maybe there are some cycles of the planets in which they are visible from earth, or of their moons, or of comets, or of nearby stars or that kind of thing.
If there were ones around each of these points that would be nice: 2, 5, 10, 20, 50, 100, 500, or 1000 years sort of thing.
Basically I am looking for "interesting" or "popular" cycles rather than just picking any of them (since every planet and moon has an orbital period). I am looking for ones that (a) we can observe most easily either directly without a telescope, or with a simple telescope/binoculars, and/or (b) have significance of some kind historically perhaps. If there is one that is historically significant or historically popular (say something Newton or Kepler talked about for example) but is difficult to see, that would be okay too.
The following is multiple choice question (with options) to answer.
What is larger then the human planet and causes cycles of day and night? | [
"the moon",
"sun",
"ocean and",
"mars"
] | B | the sun rising and setting causes cycles of day and night |
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