sains

1. Form 2 Science
Chapter 7
FORM 2 CHAPTER 7
DYNAMICS
1. (a) Name the forces shown in Diagram 1.1.
[4 marks]
(b) Diagram 1.2 shows a girl playing hockey.
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Diagram 1.2
(i) ………………………………….. (ii) …………………………………..
(iii) ………………………………….. (iv) …………………………………..
Diagram 1.1

2. Form 2 Science
Chapter 7
State two effects of force on the ball when the girl hits the ball with a hockey stick.
(i) …………………………………………………………………………………………………….
(ii) …………………………………………………………………………………………………….
[2 marks]
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3. Form 2 Science
Chapter 7
2. A worker pushes a sack of rice using a trolley to the shop as shown in Diagram 2.1.
(a) If the frictional force between the trolley and the ground is 500 N, calculate the work done
by the worker.
[2 marks]
(b) A boy tries to push the sack of rice but the sack is too heavy for him to move.
(i) Did the small boy do any work?
………………………………………………………………………………………………….
[1 mark]
(ii) Why?
………………………………………………………………………………………………….
[1 mark]
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Diagram 2.1

4. Form 2 Science
Chapter 7
(c) The worker carries a sack of rice weighing 50 kg upstairs. If the mass of the man is 65
kg, calculate the work done in Diagram2.2.
(1 kg = 10 N)
[2 marks]
(d) The worker takes 5 minutes to complete the work in (c). Calculate his power.
.
[2 marks]
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Diagram 2.2

5. Form 2 Science
Chapter 7
3. Diagram 3.1 shows a wooden block being pulled on a table top.
(a) Name the forces acting on the wooden block.
(i) …………………………………………………………………………………………………
(ii) …………………………………………………………………………………………………
[2 marks]
(b) Using , draw the direction of the frictional force acting on the wooden block in the box
provided in Diagram 3.1.
[1 mark]
(c) What will happen to the reading of the spring balance if the same wooden block is pulled
along a piece of sand paper?
………………………………………………………………………………………………………
[1 mark]
(d) Diagram 3.2 shows a man pushing a box towards the wall.
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Wooden block
Smooth table top
Spring balance
Diagram 3.1
Wall
Box
5 m
Diagram 3.2

6. Form 2 Science
Chapter 7
(i) Suggest one way on how he can reduce the force needed to push the box.
…………………………………………………………………………………………………..
[1 mark]
(ii) If the force needed to push the box is 300 N. Calculate the work done by the man in
pushing the box towards the wall.
[2 marks]
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7. Form 2 Science
Chapter 7
4. Diagram 4.1 shows some methods used to reduce friction.
(a) Name method P, Q, and R on Diagram 4.1.
[3 marks]
(b) Diagram 4.2 shows some used tyres.
(i) What has happened to the surfaces of the tyres?
………………………………………………………………………………………………….
[1 mark]
(ii) Explain your answer in (b)(i).
…………………………………………………………………………………………………….
…………………………………………………………………………………………………….
[1 mark]
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P: ……………………….. Q: ……………………….. R: ………………………..
Diagram 4.1
Diagram 4.2

8. Form 2 Science
Chapter 7
(c) Diagram 4.3 shows two persons walking.
(i) State one advantage of friction in this situation.
…………………………………………………………………………………………………
[1 mark]
(ii) State one disadvantage of friction in this situation.
…………………………………………………………………………………………………
[1 mark]
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Diagram 4.3