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. What is the centripetal acceleration at its outer edge? 2. A child playing with a top spins it so that it has a centripetal acceleration of 125.0 m/s2 at the edge, a distance of 3.00 cm from the axis of rotation. What is the speed at the edge of the top? 3. A helicopter blade has a diameter of 14.0 m and a centripeta... |
An intake fan blade on a jet engine has a mass of 7.50 kg. As it spins, the middle of the blade has a speed of 365.9 m/s and is a distance of 73.7 cm from the axis of rotation. What is the centripetal force on the blade? 2. A 0.0021-kg pebble is stuck in the treads of a dirt bike’s wheel. The radius of the wheel is 23... |
a place clear of obstructions. Table 5.3 Data for 5-3 Inquiry Lab Required Skills Initiating and Planning Performing and Recording Analyzing and Interpreting Communication and Teamwork Procedure 1 Copy Table 5.3, at the bottom of this page, into your notebook. 2 Secure the rubber stopper to one end of the string. 3 Ru... |
not move off the lip. Record the time in the “Time 1” column of Table 5.3. 10 Repeat step 9 and record the time in the “Time 2” column of Table 5.3. 11 Increase the hanging mass by 50 g, and record this mass in the “Mass” column of the table. Repeat steps 6 to 10 until all the masses are used. Analysis 1. For each tri... |
etal force. For simplicity, this is written as: Fc Ff Recall that the magnitude of the force of friction is repre FN, where FN is the normal force, sented by the equation Ff or perpendicular force exerted by the surface on the object. For an object on a horizontal surface, the normal force is equal and opposite to the ... |
)9.81(40.0 m) m s2 15 m/s Paraphrase The fastest that the car can round the curve is 15 m/s or 55 km/h. If it attempts to go faster, the force of static friction will be insufficient to prevent skidding. Practice Problems 1. An Edmonton Oiler (m 100 kg) carves a turn with a radius of 7.17 m while skating and feels his ... |
. At the top, the centripetal force is exerted by two forces working in the same direction: the track on the car, which is the normal force (F g). Both forces push the car toward the centre of the loop. N) and the force of gravity (F The speed of the car determines the amount of centripetal force needed to maintain a c... |
needed to keep the car on a track of this radius, so the car falls off. The first time through the loop, the speed is such that the roller Figure 5.28(a) coaster requires a centripetal force of 1500 N to keep it moving in a circular path. At the top of the loop, the roller coaster car will experience a centripetal for... |
’ speed is enough to create a centripetal force greater than the force of gravity to minimize the chance of the car leaving the track. The wheels of roller coaster cars also wrap around both sides of the track so the track can indeed pull upwards. Concept Check The centripetal force exerted on the Moon as it orbits Ear... |
m/s to stay on the track. You can swing a full pail of water around in a circle over your head without getting wet for the same reason that a roller coaster can go around a loop without falling off the track. Let’s examine the case of a mass on the end of a rope, moving in a vertical circle, and see how it compares to... |
and the rope will break. In what position in the bucket’s circular path is this most likely to happen? Explain. Is it necessary to know the position of an object moving in a vertical circle with uniform speed if you are determining centripetal force? Explain. 2. Forces Affecting an Object Moving in a Vertical Circle I... |
5.31. 3. A 0.98-kg rock is attached to a 0.40-m rope and spun in a vertical circle. The tension on the rope when the rock is at the top of the swing is 79.0 N [down]. What is the speed of the rock? Answers 1. 3.3 N [down] 2. 18 N [left] 3. 6.0 m/s Remember that the centripetal force is the net force and is the vector ... |
34). Positions A, B, and C are at different radii from the axis of rotation, but all the positions make one complete revolution in exactly the same time, so they have the same period. Of course, if the periods for points A, B, and C are the same, so are their frequencies, and we can make the following generalization: F... |
In earlier example problems, such as Example 5.3, a given rotational frequency or period had to be converted to speed before the centripetal acceleration or force could be determined. It would be simpler to derive the equations for centripetal acceleration and force using rotational frequency or period to save a step ... |
60 f s 0 6 m in rev 1 1 266.00 Hz D r 2 0 m 0.42 2 0.210 m ac 42rf 2 42(0.210 m)(266.00 Hz)2 5.87 105 m/s2 The magnitude of the centripetal acceleration at the tip of each compressor blade is 5.87 105 m/s2. Chapter 5 Newton’s laws can explain circular motion. 267 05-Phys20-Chap05.qxd 7/24/08 12:51 PM Page 268 5.2 Chec... |
must a toy racecar have to move successfully through a vertical loop that has a diameter of 30.0 cm? 12. Determine the centripetal acceleration acting on a person standing at the equator (r Earth 6.38 106 m). 13. An ant climbs onto the side of a bicycle tire a distance of 0.40 m from the hub. If the 0.010-g ant can ho... |
that Mars had an elliptical orbit, not a circular one. Until this time, all mathematical predictions of a planet’s position in space were based on the assumption that it moved in a circular orbit. That is why Brahe’s observations disagreed with mathematical predictions at the time. By recognizing that planets move in ... |
bits of Celestial Bodies Kepler’s Second Law Celestial Body Mercury Venus Earth Mars Ceres Jupiter Saturn Uranus Neptune Pluto Eris Sedna Eccentricity 0.205 0.007 0.017 0.093 0.080 0.048 0.054 0.047 0.009 0.249 0.437 0.857 e WEB Sedna was discovered in 2004 and is the largest object yet found in a region of space known... |
05-Phys20-Chap05.qxd 7/24/08 12:51 PM Page 271 Kepler’s Third Law Kepler’s third law states that the ratio of a planet’s orbital period squared divided by its orbital radius cubed is a constant that is the same for all the planets orbiting the Sun. Written mathematically, it is: 2 T a K 3 ra (11) e SIM where Ta is the... |
To learn more about the Titius-Bode law, follow the links at www.pearsoned.ca/ school/physicssource. Kepler’s third law states that the constant K is the same for all planets in a solar system. The period and orbital radius of Earth are well known, so they are used to compute the constant. The mean (average) orbital d... |
the mean orbital distance from Earth to the Sun (the length of the semi-major axis of Earth’s orbit). This is a more manageable unit to use. For example, Neptune is only 30.1 AU away from the Sun on average. Kepler’s constant, using units of years (a) and AU, can be deter- mined as follows: 2 T E K 3 rE )2 a (1 )3 U A... |
Planets nearest the Sun have the highest orbital speeds. The years of these planets are the shortest. Planets farthest from the Sun have the longest years. Kepler’s laws don’t apply just to planets orbiting the Sun. They apply to all bodies that orbit the same focus in an ellipse. This means that moons orbiting a plan... |
and have cleared the neighbourhood around its orbit. Pluto fails to satisfy the last criterion as its orbit is near many other Kuiper belt objects. There are now officially only eight planets in our solar system. Chapter 5 Newton’s laws can explain circular motion. 273 05-Phys20-Chap05.qxd 7/24/08 12:51 PM Page 274 Co... |
1021 3.01 1021 5.00 1019 2.14 1022 2.00 1019 1.830 106 1.565 106 2.634 106 2.403 106 2.090 105 2.560 105 5.356 105 5.600 105 7.640 105 2.575 106 7.180 105 2.400 105 5.811 105 5.847 105 7.889 105 7.614 105 2.080 105 1.352 106 1.700 105 274 Unit III Circular Motion, Work, and Energy 27.322 0.3189 1.262 1.769 3.551 7.154... |
orbital period and radius of Phobos can be used with the orbital period of Deimos to determine its orbital radius (not drawn to scale). Given TP rP TD 0.3189 d 9378 km 1.262 d Required orbital radius of Deimos (rD) Analysis and Solution Both Phobos and Deimos orbit the same object, Mars, so Kepler’s third law can be u... |
this lab is to design a method to highlight the relationship between the period and radius of planets’ orbits around the Sun. The Question How can the relationships between the orbital period and orbital radius of planets orbiting the Sun be shown by graphical means? Design and Conduct Your Investigation This lab shou... |
gravity that caused the apple to fall could also be acting on the Moon pulling it toward Earth. This revelation might seem obvious but that’s only because we have been taught that it’s true. In his day, Kepler theorized that magnetism made the Moon orbit Earth, and planets orbit the Sun! For most of the 1600s, scienti... |
Earth in kilograms, v is the speed of the Moon in metres per second, and r is the orbital radius of the Moon in metres. PHYSICS INSIGHT Since Fc Fg mv 2 r GMm r 2 and 2 r 2 m4 T 2 r GMm r 2 4 2r m 2 T GMm r 2 T 2 r 3 42 GM which is a constant containing the mass of the object causing the orbit. info BIT Pluto and its ... |
5.43 103 m/s 2. 1.30 108 m Moon r 3.844 105 km Figure 5.44 The orbital speed of the Moon can be determined from its orbital radius and the mass of Earth (not drawn to scale). Analysis and Solution Convert the radius of the Moon’s orbit to SI units. Then use the mass of Earth in equation 13. 0 10 r (3.844 105 km) k 0 m... |
The Chandra X-ray satellite takes X-ray pictures of high-energy objects in the universe. It is orbiting Earth at an altitude of 114 593 km. What is its orbital period? Answers 1. 7.69 103 m/s 2. 4.19 105 s 912 km rE 6.38 106 m Figure 5.46 LandSat follows a polar orbit so that it can examine the entire Earth as the pla... |
, how can you “weigh” Earth? Newton realized that this was possible. Let’s look at the equality Fg again, but this time we will use equation 8 for centripetal force. Fc Recall that: Fc 42mMoonr T 2 Moon where mMoon is the mass of the Moon in kilograms, and TMoon is the orbital period of the Moon in seconds. 280 Unit II... |
(1564–1642) pointed a relatively new invention at the sky. He began using a telescope to closely examine Jupiter. Only a few planets are visible to the naked eye: Mercury, Venus, Mars, Saturn, and Jupiter. Until the early 1600s, any observations of these planets were done without the aid of a telescope. Within a few m... |
the Sun. Recall that anything with mass creates a gravitational field. The strength of this field depends on the mass of the object and the separation distance from it. The orbit of Uranus was minutely perturbed. Could another as-yet-undiscovered planet be exerting a gravitational pull or tug on Uranus whenever the or... |
and extreme distance make them difficult to detect. THEN, NOW, AND FUTURE Extrasolar Planets For many centuries, humans have wondered if they were the only intelligent life in the universe. It seems unlikely, given the multitude of stars in our galaxy alone. However, for any life to exist, it’s pretty safe to assume t... |
much more massive than the planet, its orbital radius is very small. This perturbation of the star is detectable and is indirect evidence that a planet must be orbiting it. As you can imagine, for a star to have a noticeable wobble, the planet that orbits it must be relatively large and fairly close to the star. This ... |
. They map Earth, find geological formations and minerals, help us communicate over great distances and in remote areas, and help predict the movement of weather systems such as hurricanes. Opponents of the continued unregulated use of satellites argue that the cost of deploying satellites is enormous; they don’t have ... |
s rotational period (Figure 5.50). These satellites are placed in the plane of the equator, so they will have exactly the same axis of rotation as Earth, and will stay fixed over the same spot on the planet (Figure 5.51). To an observer on the ground, geostationary satellites appear motionless. axis of rotation of Eart... |
the Earth since both revolve around the same axis with the same period. To an observer on the ground, the satellite does not appear to be moving. info BIT Geostationary satellites are also referred to as geosynchronous satellites. e WEB To learn more about real-time tracking of satellites in orbit around Earth, follow... |
5.6 on page 274. 13. Using the orbital period and radius of Venus from Table 5.5 on page 273, determine the mass of the Sun. Extensions 14. As more satellites are put into space, the amount of orbital debris increases. What solutions can you suggest to decrease the amount of space junk? 15. Using a graphing calculator... |
(5.1) What force is responsible for the tug your hand feels as you spin an object around at the end of a rope? 4. (5.1) Sketch a diagram of a mass moving in a vertical circle. Draw the velocity, centripetal acceleration, and centripetal force vectors at a point on the circle’s circumference. 5. (5.2) Why do spinning t... |
the cage exerts on an 80.0-kg passenger? 19. What is the minimum speed that a glider must fly to make a perfect vertical circle in the air if the circle has a radius of 200.0 m? 20. A child spins an 800.0-g pail of water in a vertical circle at the end of a 60.0-cm rope. What is the magnitude of the tension of the rop... |
planet has an orbital period of 400.0 Earth days and an orbital radius of 1.30 1011 m. 29. The Milky Way is a spiral galaxy with all the stars revolving around the centre where there is believed to be a super-massive black hole. The black hole is 2.27 1020 m from our Sun, which revolves around it at a speed of 1234 m/... |
, refer to Student References 4: Using Graphic Organizers pp. 869–871. Use the Key Terms and Concepts listed above and the Learning Outcomes on page 240. 1. In a few sentences, summarize how frequency, period, and velocity affect centripetal acceleration. 2. Explain to a classmate in writing why the velocity at differe... |
. The complicating factor is that there are so many forms of energy it is often very difficult to keep track of what happens to the energy when it is transferred. Energy is a scalar quantity. This chapter concentrates on gravitational potential energy, kinetic energy, and elastic potential energy. In this chapter you w... |
Length of Potential Energy Bar (mm) Length of Kinetic Energy Bar (mm) Sum of Lengths (mm) start a b Think About It 1. If two cars are identical except for the size of their engines, how will that affect their performance on the highway? 2. What is the “law of conservation of energy”? When does this law apply? 3. When ... |
The elastic potential energy of the bow is transformed into the energy of motion of the arrow, called kinetic energy. As skiers ride up a lift, the lift’s motor is transforming chemical energy of the fuel into gravitational potential energy of the individuals. As they go downhill, gravity does work on the skiers trans... |
magnitude of the component of the force that acts parallel to the displacement. In Figure 6.5, where the angle between the direction of the force and the direction of the displacement is, the component of the force parallel to the displacement is given by F Fcos F d If you replace F by Fcos, the calculation for work b... |
the cord begins to stretch? Answers 1. 7.37 104 J 2. 443 N 3. 35.5º 4. 1.18 104 J Given 1.50 102 N [0°] F 25.0 m [25.0°] d Required work done by the force (W) Analysis and Solution From Figure 6.8, the angle between the force and the displacement is 25.0°. Draw a component diagram (Figure 6.9). The component that does... |
value of 9.81 m/s2 near Earth’s surface. It follows that F mg If the object is moved through a change in height h, so that d h, the change in potential energy equation becomes EP mgh Figure 6.10 A motor works transferring energy to the ride car. The gravitational potential energy gained produces the exciting free fall... |
5.00 102 kg)9.81 2.35 105 kg 2.35 105 (N m) 2.35 105 J m s2 m s2 (48.0 m) m Figure 6.11 Paraphrase The change in gravitational potential energy of the car and its passengers is a gain of 2.35 105 J. The object moved upward, gaining gravitational potential energy. If Ep1 represents the potential energy of an object at h... |
change in height. For example, the change in gravitational potential energy of a cart rolling down a frictionless ramp as in Figure 6.13 depends only on the vertical measurement, h. The actual distance an object travels, while it moves through a given change in height, does not affect its change in gravitational poten... |
to the horizontal. What change in gravitational potential energy does the block undergo? Answers 1. (a) 6.74 104 J (b) 1.24 104 J (c) 5.50 104 J 2. 54.2 m 3. 2.81 104 J h1 2.15 m floor h2 0.950 m Required (a) gravitational potential energy at the top of the hill relative to the floor (Ep1) (b) change in the gravitatio... |
W Fg 3W Fg 4W In an experiment to test this prediction, students suspended a series of masses from a spring and measured the position for each mass. Their data are shown in Table 6.2. Figure 6.15 The stretch produced by a force applied on a spring is proportional to the magnitude of the force. ▼ Table 6.2 Students’ exp... |
Elastic Potential Energy elastic potential energy: the energy resulting from an object being altered from its standard shape, without permanent deformation Force vs. Position for an Elastic System ) ( N F e c r o F F 0 Area Ep Position x (m) x Figure 6.17 The area under the force-position curve is equal to the work do... |
the spring. Therefore, the equation for the elastic potential energy stored in the spring is given by Ep 1 kx2 2 Concept Check Explain why it is incorrect to try to find the change in elastic potential energy of a stretched spring from the measurement of the change in the stretch. 300 Unit III Circular Motion, Work, a... |
energy stored in the spring? (b) If the spring contracts to a stretch of 0.150 m, what is the change in elastic potential energy? 2. An engineer is designing the suspension system for a car. He decides that the coil spring used in this car should compress 4.00 cm when a force of 1000 N is applied to it. (a) What is th... |
.0 1 m 2 0.600 Nm 0.600 J (0.200 m)2 The change in the elastic potential energy is: EP EP2 EP1 0.600 J 1.84 J 1.24 J Paraphrase (a) The energy stored in the spring at the initial stretch is 1.84 J. (b) When the stretch is reduced from 0.350 m to 0.200 m, the elastic potential energy stored in the spring reduced by 1.24... |
Energy of Impact Practice Problems 1. A 45.0-kg girl pedals a 16.0-kg bicycle at a speed of 2.50 m/s. What is the kinetic energy of the system? 2. A car travelling at 80.0 km/h on a highway has kinetic energy of 4.2 105 J. What is the mass of the car? 3. A skateboarder with a mass of 65.0 kg increases his speed from 1... |
elastic potential energy, what is the elastic constant for the trampoline? Practice Problems 1. A bow that has an elastic constant of 2500 N/m is stretched to a position of 0.540 m from its rest position. (a) What is the elastic potential energy stored in the bow? (b) If all of the elastic potential energy of the bow ... |
rase (a) The kinetic energy of the man is 2.40 103 J. (b) The elastic constant of a spring that stores 2.40 103 J of elastic potential energy when it is stretched 0.650 m is 1.14 104 N/m. 304 Unit III Circular Motion, Work, and Energy 06-PearsonPhys20-Chap06 7/24/08 12:56 PM Page 305 6.1 Check and Reflect 6.1 Check and... |
180] while that of car B is 24.0 m/s [180]. Both cars increase their velocity by 10.0 m/s [180]. (a) Calculate the gain in kinetic energy of each car. (b) If both cars gain the same amount of velocity, why do they gain different amounts of kinetic energy? 10. A cart with a mass of 3.00 kg rolls from the top of an incli... |
When the airtraffic controller tells the pilot to take off, the powerful engines can each produce more than 2.5 105 N of thrust to accelerate the plane along the runway. In order to produce the speed of about 250 km/h required for takeoff, the engines would need to convert more than 3 108 J of chemical energy from the... |
app Fg FN Fg Fg Fapp Fg Figure 6.24 If all the forces acting on a block combine to produce a net force of zero, the block moves up the incline at a constant speed. It increases its gravitational potential energy but not its kinetic energy. If, however, the force applied is now increased so that there is a Fg (Figure 6.... |
a cliff that is 25.0 m high. When the climber, whose mass is 72.0 kg, reaches the bottom of the cliff he has a speed of 5.00 m/s. What is the work done on the climber by the rope? 2. A force of 150 N [up] acts on a 9.00-kg mass lifting it to a height of 5.00 m. (a) What is the work done on the mass by this force? (b) ... |
to gain a total of 19.0 J, the sum of 9.00 J of kinetic and 10.0 J of potential energy as it moved up the ramp. 308 Unit III Circular Motion, Work, and Energy 06-PearsonPhys20-Chap06 7/24/08 12:56 PM Page 309 Calculations of Mechanical Energy To calculate the mechanical energy of an object is simply to find the total ... |
s 1 2 (5.20 kg)160 6.656 104 J 6.121 104 J 1.28 105 J m s2 (1.20 103 m) Answers 1. 7.63 1010 J 2. 150 m/s 3. (a) 5.13 103 J (b) 3.05 105 J Paraphrase and Verify The total energy of the cannon ball at the top of the trajectory is 1.28 105 J. The gravitational potential energy is positive because the cannonball is highe... |
2.40 103 N. A 7.00-kg mass is placed at the end of the spring and released. As the spring expands, it accelerates the mass so that when the spring’s compression is still 0.180 m from its equilibrium position, the mass has a speed of 6.00 m/s. (a) What is the mechanical energy in this system when the spring is compress... |
keep track of the money transfers that occur in this non-isolated room compared with those occurring in the isolated room. In physics, when the energy interactions of a group of objects need to be analyzed, we often assume that these objects are isolated from all other objects in the universe. Such a group is called a... |
science and is a powerful mathematical model for analysis and prediction of the behaviour of objects within systems. Viewed from a slightly different perspective, conservation of energy states that, in terms of mechanical energy, any gain in kinetic energy must be accompanied by an equal loss in potential energy. Ek E... |
/s (Ep2) Analysis and Solution A frictionless roller coaster can be treated as an isolated system. (a) The mechanical energy at any point is the sum of its kinetic and potential energies. Em1 Em1 Ep1 Ek1 1 mv1 2 2 mgh1 (8.00 102 kg)4.00 1 2 m s 2 (8.00 102 kg)9.81 m s2 (35.0 m) 2.810 105 J 2.81 105 J (b) The system is ... |
In an isolated system, energy is transferred from one object to another whenever work is done. 313 06-PearsonPhys20-Chap06 7/24/08 12:56 PM Page 314 e SIM Learn about the relationships among the mechanical, kinetic, and gravitational potential energies of a pendulum. Go to www.pearsoned.ca/school/ physicssource. Parap... |
system greatly simplifies the calculations of the system’s mechanical energy. It means that the force of gravity works on the pendulum without changing the energy in the system. In fact, while work done by the force of gravity may transfer energy from one form to another it never causes a change in mechanical energy (... |
ulum bob is 5.00 cm above the floor. The mass of the pendulum bob is 250 g. (a) What is the mechanical energy of the pendulum, relative to the floor, when the bob is at its highest point? (b) What is the mechanical energy of the pendulum, relative to the floor, when the bob is at its lowest point? (c) What is the kinet... |
The hill is 85.0 m above the ground. The trolley goes down the first hill and up to the crest of the second hill 64.0 m above the ground. Ignore the effect of frictional forces. What is the kinetic energy of the trolley at the top of the second hill? 4. A pole-vaulter with a mass of 56.0 kg tries to convert the kineti... |
kg 1.98 m s Paraphrase and Verify (a) At the highest point, the total energy of the pendulum is 0.613 J. (b) As the bob swings lower, gravitational potential energy is lost and kinetic energy is gained. The total energy remains 0.613 J. (c) At the lowest point, the kinetic energy is 0.491 J, the difference between its... |
set out below. Calibrate the timer: 1 Start the tape moving steadily through the timer, then connect the timer to the power supply for an exact measure of time (3 to 5 s works well). Be sure the tape does not stop moving while the timer is running. 2 Count the number of intervals between the dots (N) and divide that n... |
supply pendulum bob timer timer tape Figure 6.34 7 With ticker tape attached to the pendulum but without the timer running, do a trial run of the system. Attach the tape to the pendulum bob at its centre of mass, so that the pull of the tape does not cause the bob to twist. Use a length of ticker tape that will reach ... |
point of each chosen interval. Starting from interval 1, number the selected intervals as 2, 3, etc. For each of the chosen intervals, measure (a) the length of the interval (x), and (b) the distance (x) to the midpoint of the interval from the line indicating x 0. Record your measurements in a data table (Table 6.4). ... |
Non-conservative Forces To understand the law of conservation of energy you must understand that some forces, such as gravity and elastic forces, act within systems without affecting the mechanical energy of the system. When such forces operate, energy is conserved. These are called conservative forces. Other forces, ... |
the work done by friction, you can see that path length does affect the work done on the car. The term d, the distance through which the force of friction acts, is not the displacement, but is always the actual distance the object travels. Wf is the work done by the force of friction, Ff, on the system. Therefore: Ff ... |
well as friction, act on a system, then the total work done by all of these forces produces the change in mechanical energy. Em2 Em1 Em1 W (WA WB WC... Wf) This is simply another version of the work–energy theorem. Comparison of Energy-Position Graphs for Isolated and Non-isolated Systems Figure 6.37 shows the energy-... |
As an example of a non-isolated system, imagine a cart accelerating down an inclined plane. The force of friction removes energy from the system, but it is not sufficient to stop the cart from speeding up. The magnitude of the change in kinetic energy is less than the magnitude of the change in gravitational potential... |
golfer starts her swing until the golf ball lands on the ground at a distance from the bottom of the cliff. Include the energy transformation at the point of impact. 9. The figure below shows the energy-position graphs for two different systems. For each graph, describe what is happening to the object(s) in the system... |
were the main source of energy used to drive the pumps that removed water from mines. Thus, when James Watt (1736–1819) wanted to know how his newly improved steam engine compared with existing methods of pumping water out of mines, he compared its effectiveness to that of horses. Today, even though it is a rather awk... |
its occupants have a mass of 1300 kg. The elevator motor lifts the elevator to the 12th floor, a distance of 40.0 m, in 75.0 s. (a) What is the power output of the elevator? (b) What is the efficiency of the system if the motor must generate 9.40 kW of power to do the specified work? Given m 1.300 103 kg g 9.81 m/s2 h... |
Motor The Question How much power can a small electric motor generate? The Problem The problem in the lab is to measure the power output of a motor by timing how long it takes for the motor to do a fixed amount of work. Variables The variables for measuring power are the work done against gravity (EP) and the time (t)... |
difficult to time the motion of the washers. If the speed is too slow, then the motor may not run smoothly.) 326 Unit III Circular Motion, Work, and Energy 06-PearsonPhys20-Chap06 7/24/08 12:56 PM Page 327 6 Pull the thread to unwind thread from the dowel until 2. Make a graph of the power output versus the mass the w... |
or fuel cells) be more effective? With a group of classmates, investigate how best to improve the energy efficiency of automobiles. Use your library and the Internet. Present the results of your investigation in a report using presentation software such as PowerPoint ™. Begin your search at www.pearsoned.ca/school/ ph... |
0 Ff Ff (2.051 103 N) (4.50 102 N) 2.051 103 N 4.50 102 N 2.50 103 N Practice Problems 1. What is the power output of an electric motor that lifts an elevator with a mass of 1500 kg at a speed of 0.750 m/s? 2. An engine’s power is rated at 150 kW. Assume there is no loss of force due to air resistance. What is the gre... |
involved in the jump will you need to determine? 2. What equipment might you require to measure those factors? 3. How would you measure the dancer’s maximum power output compared with the power he can generate over a sustained period of time? Figure 6.43 e WEB To learn more about power generated in human activities, f... |
(Prony brake) to measure the power output of the motors they install in their vehicles. A Prony brake for bicycles would be a useful thing. The Problem How does the gear used by a cyclist affect the power output at the drive wheel of the bicycle? In which gear do cyclists generate the greatest power? Criteria for Succ... |
report. 6. An electric motor has a power rating of 1.50 kW. If it operates at 75% efficiency, what work can it do in an hour? 7. A motor of a car must generate 9.50 kW to move the car at a constant speed of 25.0 m/s. What is the force of friction on the car? Extension 8. A cannon fires a ball with a muzzle velocity of... |
of his jump. (d) Two students calculate the gravitational potential energy of a mass resting on a shelf. One student calculates that it has 12.0 J of energy while the other calculates the gravitational potential energy to be 35.0 J. Is it possible that they are both right? Explain. (e) Two masses, A and B, are at rest... |
) An elevator takes 2.50 min to travel from the ground floor to the 10th floor of an apartment block. The tenants want the landlord to increase the speed of the elevator but the landlord argues that speeding up the elevator means that it will need to work harder and that would take more energy. Is he correct? Explain. ... |
the elastic constant for the cord? HINT: Assume an isolated system. At the lowest point the bungee cord must convert all of the jumper’s lost gravitational potential energy into elastic potential energy in the cord. 9. A motorcycle stuntman wants to jump over a line of city buses. He builds a takeoff ramp that has a s... |
the eTest links at www.pearsoned.ca/school/physicssource. Chapter 6 In an isolated system, energy is transferred from one object to another whenever work is done. 333 06-PearsonPhys20-Chap06 7/24/08 12:56 PM Page 334 UNIT III PROJECT Building a Persuader Apparatus Scenario It is 1965. Seatbelts are oddities used only ... |
Assess the success of your project based on a rubric* designed in class that considers: research strategies thoroughness of the experimental design effectiveness of the experimental technique effectiveness of the team’s public presentation Procedure 1 Research existing safety features used in automotive production. Id... |
; QuickLab 5-1; Inquiry Lab 5-2 Centripetal acceleration and centripetal force are both directed toward the centre of the circle. Figures 5.8–5.11; Table 5.2; 5.2 Circular Motion and Newton’s Laws The velocity of circular motion can be determined by dividing the circumference by the period. The centripetal acceleration... |
Analysis; Figures 5.48–5.51 Chapter 6 In an isolated system, energy is transferred from one object to another whenever work is done. Work Potential energy Kinetic energy 6.1 Work and Energy Work is the transfer of energy that occurs when a force acts over a displacement. It is a scalar quantity measured in joules. (1 ... |
own words, define these terms: artificial satellite axis of rotation axle centripetal acceleration centripetal force conservation of energy conservative force cycle eccentricity efficiency elastic potential energy ellipse energy frequency gravitational potential energy isolated system Kepler’s constant Kepler’s laws k... |
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