Split (1)

train · 4.29k rows

text stringlengths 790 2.88k
= V3 The total current passing through the circuit will be the sum of the individual currents passing through each resistor. IT = I1 + I2 + I3 If we return to the analogy of a river, a parallel circuit is the same as the river breaking into three streams, which later rejoin to one river again. The amount of water ﬂowi...
circuit could also be found by using the total voltage drop and the total current. RT = VT IT 7:5 A = 12 W = 90: W Summary • Parallel electrical circuits have multiple paths the current may take. • VT = V1 = V2 = V3. • IT = I1 + I2 + I3. + 1 • R3 = 1 R1 = 1 R2 1 RT. Practice MEDIA Click image to the left for more cont...
by CK-12 Foundation - Samantha Bacic. http:// www.shutterstock.com. Used under license from Shutterstock.com 3. CK-12 Foundation - Samantha Bacic.. CC-BY-NC-SA 3.0 31 CONCEPT 11 Resistors in Parallel Students will learn how to analyze and solve problems involving circuits with resistors in parallel. Students will lear...
, using Ohm’s law, convert the power formula into a form that does not depend on current. P = IV = V R Substituted I = V =R into the power R formula. P90W = V 2 10W = 40W 90W R90W Note: If you add up the power dissipated by each resistor, it equals the total power outputted, as it should–Energy is always conserved. 90W...
values. Combined Series-Parallel Circuits Most circuits are not just a series or parallel circuit; most have resistors in parallel and in series. These circuits are called combination circuits. When solving problems with such circuits, use this series of steps. 1. For resistors connected in parallel, calculate the sin...
uits Review 1. Two 60.0W resistors are connected in parallel and this parallel arrangement is then connected in series with a 30.0W resistor. The combination is placed across a 120. V potential difference. (a) Draw a diagram of the circuit. (b) What is the equivalent resistance of the parallel portion of the circuit? (...
www.ck12.org The names “CK-12” and “CK12” and associated logos and the terms “FlexBook®” and “FlexBook Platform®” (collectively “CK-12 Marks”) are trademarks and service marks of CK-12 Foundation and are protected by federal, state, and international laws. Any form of reproduction of this book in any format or medium,...
a force on each other. The magnetic force can be either attractive or repulsive. If two north poles or two south poles are brought near each other, the force will be repulsive. If a north pole is brought near a south pole, the force will be attractive. 1 www.ck12.org The Earth’s geographic north pole (which is close t...
a magnet to attract a non-magnetized piece of iron. You have most likely seen a magnet pick up a paper clip. The presence of the magnet aligns the domains in the iron paper clip and it becomes a temporary magnet. Whichever pole of the magnet is brought near the paper clip will induce magnetic properties in the paper c...
) none of these are true. 2. A material that can be permanently magnetized is generally said to be (a) magnetic. (b) electromagnetic. (c) ferromagnetic. (d) none of these are true. 3. The force between like magnetic poles will be (a) repulsive. (b) attractive. (c) could be repulsive or attractive. 4. Why is a magnet ab...
Composite created by http://www.shutterstock.com. Used under licenses from Shutter- CK-12 Foundation - Samantha Bacic. stock.com 5 CONCEPT 2 www.ck12.org Magnetic Fields Students will learn the idea of magnetic ﬁeld lines, how they behave in the situation of permanent magnets and current carrying wires and also how to...
necessary to represent such three dimensional ﬁelds on a two dimensional sheet of paper. The following example illustrates how this is done. In the example above, a current is running along a wire towards the top of your page. The magnetic ﬁeld is circling the current carrying wire in loops which are perpendicular to ...
current in the wire? Answers to Selected Problems 1. Both pointing away from north 2. 3 106T 3. 5000 A 9 Physics Unit 15: Electromagnetism Patrick Marshall Jean Brainard, Ph.D. Ck12 Science James H Dann, Ph.D. Say Thanks to the Authors Click http://www.ck12.org/saythanks (No sign in required) AUTHORS Patrick Marshall ...
www.ck12.org 1 4 8 13 18 22 26 Contents 1 Electromagnetic Induction 2 Electromagnets 3 Current and Magnetism 4 Electric Motors 5 Electromotive Force 6 Electric Generators 7 Transformers iv www.ck12.org Concept 1. Electromagnetic Induction CONCEPT 1 Electromagnetic Induction • Deﬁne electromagnetic induction. • Explain...
important devices depend on electromagnetic induction: electric generators and electric transformers. Both devices play critical roles in producing and regulating the electric current we depend on in our daily lives. Electric generators use electromagnetic induction to change kinetic energy to electrical energy. They ...
. • Determine the direction of the magnetic ﬁeld inside a solenoid given the direction of current ﬂow in the coil wire. • Understand why an electromagnet has a stronger magnetic ﬁeld than a solenoid. One of the most famous electric car companies is Tesla, named after Nikola Tesla. These electric cars, and all others, r...
strong magnetic ﬁelds, and that the magnetic ﬁeld can be turned on and off. When the current ﬂows through the coil, it is a powerful magnet, but when the current is turned off, the magnetic ﬁeld essentially disappears. Electromagnets ﬁnd use in many practical applications. Electromagnets are used to lift large masses ...
.org Concept 2. Electromagnets • solenoid: A current-carrying coil of wire that acts like a magnet when a current passes through it. • electromagnet: A temporary magnet consisting of an iron or steel core wound with a coil of wire, through which a current is passed. • magnetic levitation: The suspension of an object ab...
second right hand rule, while its magnitude will depend on the length of the wire (denoted L ), the strength of the current, the strength of the ﬁeld, and the angle between their directions: Two current-carrying wires next to each other each generate magnetic ﬁelds and therefore exert forces on each other: 8 Concept 3...
Now we will calculate the net force on the loop using the equation given above. We’ll consider up the positive direction. SF = I2L( SF = Fbottom Ftop SF = I2LBbottom I2LBtop SF = I2L(Bbottom Btop) µoI1 2pR µoI1I2L 2pR µoI1I2L 4pR µoI1 2p2R 1 2 SF = SF = (1 ) ) start by summing the forces on the loop substitute in the ...
the current in the lower wire? 5. Show that the formula for the force between two current carrying wires is F = µoLi1i2 2pd, where d is the distance between the two wires, i1 is the current of ﬁrst wire and L is the segment of length of the second wire carrying a current i2. (Hint: ﬁnd magnetic ﬁeld emanating from ﬁrs...
of an electric motor. As gas prices continue to rise, electric cars and hybrids are becoming increasingly popular. These cars are certainly a part of our future. On the left in the image above is an all-electric vehicle, and on the right is a hybrid vehicle that uses gas part time and electricity part time. Electric M...
Where the rotating coil (in grey) meets the wires attached to the power source (black), we ﬁnd a split ring commutator. The coil turns, but the commutator and power source do not. As the coil turns, it moves off of the blue box connector and as it continues to turn, it connects to the other blue box connector. As the ...
af_%26_Chevy_Volt_charging_trimmed.jpg. CC-BY 2.0 16 www.ck12.org Concept 4. Electric Motors 2... CC BY-NC-SA 3. CK-12 Foundation - Samantha Bacic.. CC-BY-NC-SA 3.0 4. CK-12 Foundation - Samantha Bacic.. CC BY-NC-SA 3.0 5. Image copyright Sim Kay Seng, 2013. http://www.shutterstock.com. Used under license from Shutter-...
in the direction of the magnetic ﬁeld, point thumb in the direction of wire movement, and palm shows direction of electron ﬂow.) No current will ﬂow, of course, unless the section of wire is part of a complete circuit. This process allows us to convert mechanical energy (the motion of the wire) into electrical energy ...
a magnetic ﬁeld is produced by the work done on the charges by whatever is pushing the wire through the ﬁeld. • The EMF (or voltage) depends on the magnetic ﬁeld strength, B, the length of the wire in the magnetic ﬁeld, l, and the velocity of the wire in the ﬁeld, EMF = Blv. Practice MEDIA Click image to the left for ...
generated in a loop of conducting material by movement of the loop across a magnetic ﬁeld. References 1. Courtesy of the NRC. http://commons.wikimedia.org/wiki/File:Modern_Steam_Turbine_Generator.jpg. Public Domain 2. CK-12 Foundation - Samantha Bacic.. CC-BY-NC-SA 3.0 3. CK-12 Foundation - Samantha Bacic.. CC-BY-NC-S...
��eld and therefore, not cutting across the ﬁeld at all. The EMF at this point will be zero. As that same wire then cuts down through the ﬁeld as it continues to spin, the left hand rule indicates that the electron ﬂow will be from the back to the front in that side of the coil. In this second half of the arc, the dire...
: a. Veff = 0:707 Vmax = (0:707)(34:0 V ) = 24:0 V b. Ieff = 0:707 Imax = (0:707)(0:17 A) = 0:120 A c. R = V 0:120 A = 200: W I = 24:0 V Summary • Electric generators convert mechanical energy to electric energy. • The generator consists of some number of wire loops wrapped around an iron core and placed in a strong ma...
eld, and relative motion (e) none of these will produce EMF mechanically 2. Increasing which of the following will increase the output of a generator? (a) EMF (b) strength of the magnetic ﬁeld (c) resistance of the conductor (d) load on the meter (e) none of these 3. The current in the rotating coil of all generators i...
low voltage and high current. Since power companies do not wish to waste power as it is transmitted to homes and businesses, they deliberately ’step up’ the voltage and reduce the current before transmitting the power over extended distances. That type of power transmits well without great loss of energy but it cannot...
st circuit ceases to ﬂow and the magnetic ﬁeld collapses back through the wire to zero. As the magnetic ﬁeld collapses, it passes through the wire and once again we have relative motion between the wire in the second circuit and the magnetic ﬁeld. Therefore, we once again have a short jolt of current induced in the sec...
coil is 90.0 V, what is the voltage on the secondary coil? b. If the current in the secondary circuit is 2.00 A, what is the current in the primary coil? c. What is the power in the primary circuit? d. What is the power in the secondary circuit? Solution: = NP NS = NP NS VS = (90:0 V )(3000) a. VP VS IS IP = 30:0 A b....
the voltage across the secondary? (b) The current in the secondary is 36 A. What current ﬂows in the primary? 2. The secondary of a step-down transformer has 500 turns. The primary has 15,000 turns. (a) The EMF of the primary is 3600 V. What is the EMF of the secondary? (b) The current in the primary is 3.0 A. What is...
is used as a rear view driving mirror. Any object in front of the mirror, i.e, lying behind the car, forms an upright diminished virtual image between F and P (Fig. 1.37). For example, another car behind is seen upright and small in size in the mirror. The driver of a car has a wider view of all the objects lying behi...
The principal focus, F, is a fixed point on the principal axis where a set of incident rays parallel and close to the principal axis converge in a concave mirror and appear to diverge on in a convex mirror. • The principal focus is real for a concave mirror and virtual for a convex mirror. • The focal length, f, of a ...
A. f = r 2 B. f = 2r C. f = r D. None of the above. 3. In a concave mirror, when the object is placed between the principal focus and the pole, the image formed is A. real and diminished C. virtual and upright B. real and magnified D. virtual and inverted 4. In a concave mirror, when the object is placed at 12 cm from...
14. Fig. 1.40 shows the graph of real image distance v against the object distance u for a concave mirror. Fig. 1.40 Explain why the coordinate P is for a magnified image. 15. (a) Define magnification. 30 PFC(a)PFC(b)PFC(c)PFC (d)0uPv (b) An object of height 3 cm is placed at 20 cm in front of a concave mirror. The re...
to view the images of his face. If his face is 18 cm from the mirror, determine the image distance and the magnification of his face. 23. The real image produced by a concave mirror is observed to be six times longer than the object when the object is 34.2 cm in front of a mirror. Determine the radius of curvature of ...
lenses To identify and describe types and shapes of lenses Activity 2.2 (Work in groups) Materials • Charts showing converging and diverging beam through lens. • Convex lenses Steps • Plane lenses • Spherical lenses 1. Place some lenses available in your school on a labeled white plane paper. Trace their outlines. Wha...
6: Refraction of light through lenses 2.3 Terms used in thin lenses Activity 2.3 To find out the meaning of the terms used in thin lenses (Work in pairs or in groups) Materials • Magnifying lens • Double convex lenses • Sunshine Steps • Piece of paper 1. This activity is done outside the classroom during daylight. 2. P...
iates the light passing through it towards its base. A convex lens may be regarded as being made up of large portions of triangular prisms as 37 shown below. The emergent beam, therefore, becomes convergent in a convex lens (Fig. 2.9 (a)). The reverse is the effect in a concave lens (Fig. 2.9(b)). (a) (b) Fig. 2.9: Act...
focal length of a lens (f) This is the distance from the optical centre to the principal focus of the lens (see Fig. 2.10(a) and 2.11(b). Biconvex and biconcave lenses have a focal length on each side of the lens. The concept of centres of curvature of the surfaces is required only in drawing the principal axis. Other...
rays from the object. From the three standard rays discussed above, any two incident rays and their corresponding refracted rays can be drawn to locate the image. If the refracted rays converge, a real image is obtained. If the refracted rays diverge, then a virtual image is obtained. 41 2.5.1 Convex lens Activity 2.5...
F u 2F Fig. 2.19: Object beyond 2F 4. Repeat step 3 by placing the candle at 2F and observe what happens. What are the characteristics of the images formed? Fig 2.20 shows the ray diagram to locate the images when the object is beyond C. B 0 2F F P F 2F I M Fig. 2.20: Object OB just beyond 2F 43 Image characteristics ...
the candle close to the lens, between F and P. Can you get an image on the screen? Describe its characteristics. 45 2. Is the image real or virtual? 3. Where is the image formed? 4. Explain your observations. Lens Eye F Object F Upright, virtual and enlarged image Fig. 2.24: Object between F and P The image formed is ...
A concave lens has a focal length of 2 cm and real object 1.0 cm tall is placed at 3 cm from the centre of the lens. By means of an accurate scale diagram, find the position, size and the nature of the image formed. 47 Solution Scale chosen: 1 cm to represent 1 cm Similar to Example 2.1, draw minimum two incident rays...
are similar (3 angles are equal) ∴ DP IM = PF IF …………………………………… (2) Since DP = OB, from equations (1) and (2), = OP IP u v = PF IF f v – f Cross multiplying, uv – uf = vf Dividing both sides by uvf uv uvf 1 – = ⇒ – = u uf uvf vf uvf 1 f 1 v. Hence 1 f 1 = + u 1 v. This is the Lens formula, where u stands for the dista...
is bigger than the object. Linear magnification (m) is defined as the ratio of the height of the image to the height of the object. To derive magnification formula Activity 2.10 (Work in groups) Material • Graph papers Steps 1. Draw three vertical lines on a graph paper. 18 cm 6 cm 2 cm A B C Fig. 2.31 2. How many tim...
Since m = 1; then v = u This occurs when object is at 2f. Hence 2f = 30 ∴ f = 15 cm B O P 30 cm I M u v Fig. 2.33: Image formed by convex lens 53 Example 2.7 An object of height 1.2 cm is placed 2 cm from a convex lens and real image is formed at 36 cm from the lens. Calculate (a) the focal length of the lens (b) magn...
is the power of a lens Activity 2.11 (Work in groups) Material • A lens Steps 1. Discuss with your classmates what the power of the lens is. 2. Is it possible to increase the power of a lens? Discuss. 3. Share your findings with other classmates. 55 The ability to collect rays of light and focus them at a point in the...
35 7. Copy the table below and put a tick () in three of the boxes to describe the image formed by a diverging lens. Table 2.1 Magnified Diminished Upright Inverted Virtual Real 8. Draw a diagram to show how a convex lens produce a virtual image. 9. Fig. 2.36 shows two rays of light approaching a thin diverging lens. ...
b) the magnification produced by the lens. 18. A real object placed 8 cm in front of a converging lens produces an image at a distance of 2 cm from the lens and on the same side as the object. Calculate the focal length of the lens. 19. A diverging lens of focal length 24 cm forms an image at 18 cm from the lens. Calcu...
so as to admit as much light as possible. An image formed by the eye lens leaves an impression on the retina for about 0.1 second. This persistence of the vision enables us to “see” cinema or television pictures which appear to change smoothly from one image to the next without 59 any interruption. In a cinema theatre...
ia) (see Fig. 2.40, (a) (b) ). (a) Short-sightedness (b) Long-sightedness Fig. 2.40: Short-sightedness and long-sightedness (a) Short-sightedness or Myopia A person suffering from short-sightedness can only see nearby objects. The image of a distant object is formed in front of the retina as shown in Fig. 2.33 (a). Thi...
. 2.43: A lens camera A camera consists of a converging lens and a light sensitive film or plate enclosed in a light-tight box, blackened from inside. The lens focuses light from an object to form a real, diminished and inverted image on the film. Focusing of objects is done, by adjusting the distance between the lens ...
distance in part (a). Hence the image distance, v, must be increased. To achieve this, the lens has to be moved forward towards the person. 3. Simple microscope A magnifying glass also known as a simple microscope is an instrument used to view the details of very small objects. It consists of a single converging lens ...
ification, m = 1 + v f = 1 + ( 25 5 ) = 1 + 5 = 6 Hence the magnification produced by the lens = 6. 4. Compound microscope In a simple microscope, the magnifying power cannot be increased beyond a certain limit, by decreasing the focal length of the lens. This is due to the mechanical difficulties of using a lens of ve...
distance of 8.0 cm. A real object of size 1.0 mm is placed 3.0 cm from the objective lens. (a) Use the lens formula in turn for each lens to find the position of the final image formed. (b) Calculate (i) the magnification produced by the arrangement of these lenses and (ii) the size of the final image viewed by the ey...
away) Beyond 2F At 2F Between 2F and F At F Between F and P Table 2.3 Position of image F Nature of image formed real and inverted diminished Size of image formed compared to object Between F and 2F At 2F Beyond 2F At infinity (far away) Same side as object real and inverted diminished real and inverted Same size real...
. The focal length of the lens L1 is 2 cm and that of L2 is 2.8 cm. An object 1.0 cm high is placed 3 cm from lens L1. Fig. 2.51: Equilateral glass prism (a) Construct a ray diagram to scale, on a graph paper to show the position of the final image as seen by the eye of a person. (b) Determine the magnification obtaine...
ruler balance? Why do you think it balances at that point? 2. Press the ruler at one end. Observe what happens to the ruler. 3. Repeat the experiment by pressing the ruler on the other end. Why do you think the ruler behaves in such a manner? 74 Moment of a Force Fig. 3.1: Balancing a ruler on a finger In both cases, ...
crum Solution F = Weight of dog = mg 1.2 m Fig. 3.3: Moment of force = 10 kg × 10 N/kg = 100 N Moment of the force about the fulcrum = Force × perpendicular distance from the fulcrum = 100 N × 1.2 m = 120 Nm in the clockwise direction. Exercise 3.1 1. Define ‘moment of a force’ and state its SI unit. 2. A force of 20 N...
mass at a point B near the 0 cm mark (Fig. 3.8 (a)). What has happened? The system turns in the anticlockwise direction. Now adjust the position of B till the system balances horizontally as shown in Fig. 3.8 (b). Explain the observations. (a) B O 200 g mass f = 2N P A 100 cm (b) 0 B P A F = 1N 2N F = 1N Fig. 3.8: Pri...
you say about F1 × PC + F2 × PD and F3 × PA + F4 × PB? 79 A B 100 cm C F1 P 50 cm D F2 Fig. 3.9: Balanced metre rule under action of forces. F3 F4 From Activity 3.2 and 3.3 we can conclude that the sum of the clockwise moments about a point is equal to the sum of the anticlockwise moments about the same point, when th...
masses are placed at A, B and C as shown in Fig. 3.10. Find the value for the weight W of the mass M placed at C so that the metre rule is balanced horizontally. 0 cm 50 cm A 2N 10 cm P B 1N 30 cm 40 cm Fig. 3.10: Principle of moment Mass M 100 cm C W Solution Taking moments about P, when the metre rule is in equilibr...
m, using a string, from a point A. Suspend a known mass M on the other side of the metre rule and adjust the position of the mass M till the metre rule is horizontal as shown in Fig. 3.13. 82 0 cm A object of mass, m P 50 cm B 100 cm mass M mg Mg Fig. 3.13: Finding unknown mass m. 2. Record the distances PA and PB. Re...
16 3.3 Couple Couple refers to two parallel forces that are equal in magnitude, opposite in sense and do not share a line of action. Its effects is that it creates rotation without translation as shown in Fig. 3.17. 84 Fig. 3.17: A couple A couple produces a turning effect on a body. Moment of a couple Fig. 3.18 shows ...
. Fig. 3.21: Moment of couple of a tap 14 cm 14 cm 8N Fig. 3.22: Torque 3. A steering wheel of a truck has a diameter of 30 cm. If the driver is holding the wheel with both hands, while negotiating a corner, calculate the force applied by the right hand if the left hand is pulling the wheel by a force equal to 200 N. 3...
pivoted at the 30 cm mark is kept horizontal by placing a 50 g mass on the 80 cm mark. Calculate the mass of the metre rule (Fig. 3.24). Fig. 3.24: Determining the mass of the metre rule Solution Let the mass of the metre rule be m Force due to m = m × g where g = 10 N/kg = 10 m newtons Force due to 50 g mass = PA = 1...
at the end B. The centre of gravity, G, is shown. 90 Fig. 3.27: Centre of mass of a plank Calculate the: (a) weight and (b) mass of the plank. 3.5 Applications of moment of a force The following are some of the common examples which illustrate the turning effect of a force i.e moment of a force: 1. Opening or closing ...
effort be used in working with them. 92 Exercise 3.5 Sketch and locate the effort, pivot, load in each of the following tools and machines. (a) (d) (g) (b) Water tap (e) (h) (c) See-saw (f) Hammer (i) Bottle opener Spanner Spade pliers Broom (j) Arm Spoon Topic summary • The moment of a force about a point is the turn...
Calculate M. 7. Fig. 3.32 shows a uniform metallic metre rule balanced when pivoted at the 30 cm mark under the conditions shown on the diagram. Fig. 3.31: Moments in a uniform rule (a) Redraw the diagram showing all the forces acting on the metre. (b) Calculate the weight W of the metre rule. 8. Name four importance ...
weight of the body. How is this weight distributed throughout the body? The answer to this question is found in the following activity. 4.1.1 To investigate where the weight of a body acts Activity 4.2 To find the centre of gravity of a regular body (Work in pairs or in groups) Materials: A table, thin rectangular car...
However, the two centres are at different locations for the same object if the object is placed in a place with non-uniform gravitational field strength. 4.2 Centre of gravity (c.g) of regular lamina Activity 4.3 To locate the centre of gravity of a regular lamina (Work in groups) Materials: manila paper, ruler, penci...
turn freely when supported through a drawing pin. 3. Suspend the lamina on the clamp using the drawing pin through each hole at a time. 4. Suspend a plumbline (a thin thread with a small weight at one end) from the point of support, P as shown in Fig. 4.4(a), and draw the line of the plumbline on the lamina by marking...
on the state of equilibrium of a body Activity 4.6 (Work in groups) To define and describe three states of equilibrium Materials: Internet, reference books Steps 1. Conduct a research from books and the internet on the meaning of the term equilibrium in regard to forces acting on an object. 2. State the three states o...
, the object falls back to its original position to keep its centre of gravity as low as possible. This type of equilibrium is known as stable equilibrium. Thus, the funnel in Activity 4.7 Fig. 4.6 (a) was in stable equilibrium. Our finances and keeping the environment clean!! Note that we have used a plastic thistle f...
of each. (a) (d) (b) (e) (g) (h) (c) (f) (i) Fig 4.9: Various types of figures 2. Fig 4.10 shows a Bunsen burner at different states of equilibrium. (i) (ii) (iii) Fig 4.10: A bunsen burner at different states of equilibrium 103 (a) Name the states in which the Bunsen burner is at in (i), (ii) and (iii). (b) Describe ...
applications of position of centre of gravity. 2. In your research also find out: (a) Why a bird toy balances on its beak? (b) Why it is not advisable to stand on a small boat on the surface of the water? (c) Why one leans to the opposite direction when carrying a load? (d) Why the bus chassis is made heavier than the...
gravity, c. g, of a body is the point where the whole weight of the body appears to act from. • Centre of mass of an objects is the point where all the mass of the object is concentrated. • The centre of gravity of a regular lamina or object is at its geometric centre. • The centre of gravity of a lamina can be found ...
Understand the concepts of work, energy and power. Skills • Design tests to relate work done to the magnitude of a force and the distance moved, power to work done and time taken, using appropriate examples. • Observe carefully. • Predict what might happen. • Use appropriate measures. • Collect and present results app...
is the person doing work? Explain. 9. Give other examples of doing work. Work is only said to have been done when an applied force moves the object through some distance in the direction of force. Therefore in Activity 5.1, work was done in steps 2, 3 and part of 4 (when carrying the desk). However, no work was done w...
the materials provided think of a set-up to do the investigation. Set-up the apparatus and sketch the set-up. 3. Write a brief procedure to execute in doing the activity. 4. Correctly execute the procedure and answer the following questions. 5. Using relevant formula, calculate the work done in pulling the block. What...
SI unit. 3. How much work is required to lift a 2 kilogram mass to a height of 10 metres (Take g=10 m/s2). 4. A garden tractor drags a plough with a force of 500 N at a distance of 2 metres in 20 seconds. How much work is done? 116 5.1.2 Work done against the force of gravity Activity 5.3 (Work in pairs) To determine ...
1.4 m = 560 J Example 5.6 A force of 200 N was applied to move a log of wood through a distance of 10 m. Calculate the work done on the log. Solution W = F × d = 200 N × 10 m = 2 000 J Exercise 5.2 1. Define work done and give its SI unit. 2. Calculate the work done by a force of 12 N when it moves a body through a di...
Work done by the applied force is given by Work done = F × d The work done against the gravitional force is given by: Work done = weight of the object × vertical height Work = mgh In case the inclined plane is frictionless force: Work done by the applied force = work done against gravity 119 In case there is some fric...
kg 8 m Fig. 5.7: Work done on an inclined (e) Frictional force between the body and the track. 3. A block of mass 60 kg was raised through a vertical height of 7 m. If the slant height of a frictionless track is 21 m, and the force used to push the block up the plane is 800 N, calculate the work done in pushing the bl...
Watts. 1watt = 1 joule second Large units used are kilowatt and megawatt. 1 kilowatt = 1 000 W 1 megawatt = 1 000 000 W Example 5.8 What is the power of a boy lifting a 300 N block through 10 m in 10 s? Solution Force = 300 N, Distance = 10 m, Time = 10 s Work done by the boy = F ×d = 300 ×10 Power = = 3 000 J work ti...
, n = number of steps If x is in metres, W in newtons and t in seconds then power is in watts. 124 Example 5.9 A girl whose mass is 60 kg can run up a flight of 35 steps each of 10 cm high in 4 seconds. Find the power of the girl. (Take g = 10 m/s2). Solution Force overcome (weight) = mg = 60 kg × 10 N/kg = 600 N Total...
Machine A B C D Work 1 000 joules 1 000 joules 2 000 joules 2 000 joules Table 5.1 Time 5 sec 10 sec 5 sec 10 sec 5.3 Energy Activity 5.7 (Work in pairs) To brainstorm about energy Materials: Reference materials, a pen, desk or slopy platform Steps 1. What enables your body to perform various functions besides keeping...
basin, water, convex lens, thin piece of paper Steps 1. On a bright sunny day, fill a plastic basin with cold water and place it in an open place with no shade. Dip your hand into the water after 2 hours. What is the temperature difference of the water initially and after 2 hours? 2. Get a convex lens on the same day ...
object to a cooler one. Heat energy is a form of energy that is transferred from one body to another due to the difference in temperature. 5.4.4 Electrical energy Activity 5.11 To demonstrate production of light by electrical energy (Work in groups) Materials: bulb, electric wire, cells (battery), switch, bulb holder ...
temperature reading. The chemical reaction of vinegar and steel wool generates energy in form of heat. This causes temperature to rise as shown by the thermometer. Chemical energy is a type of energy stored in the bonds of the atoms and molecules that make up a substance. Once chemical energy is released by a substanc...
This implies that the stone had stored energy due to its position that makes it to start moving down after it has been released. The energy possessed by a body (e.g. a stone) due to its position above the ground is called gravitational potential energy. In other words potential energy is energy by virtue of position. ...
30 kg through a vertical distance of 6.0 m. (a) How much work is done on the body? (b) What is the P.E stored in the body? (c) Comment on the two answers. Solution (a) Work done = F × d = mg × d = 30 × 10 × 6 = 300 × 6 = 1 800 J (b) P.E = mgh = 300 × 6 = 1 800 J (c) The work done against gravity is stored as P.E in th...
above, you should have observed that the trolley starts to move once given a slight push. It possess energy as it moves. The energy which is possessed by a moving object due to its speed is called kinetic energy (KE). In other words we can define kinetic energy as energy by virtue of motion. Examples of objects that p...
E t or Energy = pt For example, when the light bulb is connected to an electric circuit, energy is transferred from the circuit to the light bulb filament. The filament converts the electrical energy supplied to the light bulb into heat and light. The power used by the bulb is the amount of electrical energy transferr...
(b) The generation of energy from each source. 8. Let your secretary write down a summary of your discussion and present it to the whole class. 9. State and explain various types of primary and secondary sources of energy? The word ‘source’ means the beginning of something e.g. the stream begins from the mountain or h...
Nuclear plant The sun is the biggest source of energy and has played an important role in shaping our life on earth since the dawn of time. The sun gives off radiant energy in form of electromagnetic waves. The light energy (visible spectrum) part of the spectrum can be converted directly into electricity in a single ...

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.