# CBSE Worksheet for chapter-5 Force and Laws of Motion class 9

## Find CBSE Worksheet for chapter-5 Force and Laws of Motion class 9

CLASS-9

BOARD: CBSE

Physics Worksheet - 5

TOPIC: Force and Laws of Motion

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SUMMARY

• Impulse – Introduction, Definition, Impulse and momentum, Application of impulse in daily life
• Newton’s Third law of motion – Introduction, Explanation, Examples
• Principle of conservation of momentum, Illustrations on conservation of momentum.

#### SECTION I – OBJECTIVE

1. When a bullet is fired from a gun. The gun recoils to:
1. Conserve mass
2. Conserve momentum
3. Conserve K.E
4. None of these
2. A bullet in a motion hits and gets embedded in a solid resting on a frictionless table. What is conserved?
1. Momentum and K.E.
2. Momentum alone
3. K.E. alone
4. None of these
3. If the action and reaction force were to act on the same body:
1. The resultant would be zero
2. The body would not move at all
3. Both A & B are correct
4. Neither A nor B is correct
4. A man is standing on a boat in a still water. If he walks towards the shore the boat will:
1. Move away from the shore.
2. Remains stationary.
3. Move towards the shore.
4. Sink.
5. A rocket is ejecting 0.05Kg of gases per second at a velocity of 400m/s. The force on the rocket is
1. 20 Dyne
2. 20 N
3. 20 Kg-wt
4. NOT
6. Newton used ‘quantity of motion’ for:
1. Momentum
2. Force
3. Acceleration due to gravity
4. None of these
7. Kg weight is unit of:
1. Mass
2. Weight
3. Both A and B
4. Neither A and B
8. 1 kg wt is equal to
1. 9.8 N
2. 1 N
3. 5 N
4. 20 N
9. China wares and glass wares are packed with soft material when transported. This is done to:
1. Increase impulse
2. Reduce impulsive force
3. For cost cutting
4. None of these
10. A book of weight 10 N is placed on a table. The force exerted by the surface of the table on book will be:
11. Zero
12. 10 N
13. 20 N
14. None of these

#### SECTION II - SUBJECTIVE

1. Explain one application of law of conservation of momentum.
2. State third law of motion. Give two examples in support of this law.
3. State the principle of conservation of linear momentum, and derive it.
4. State any three applications of impulse in our day to day life.
5. A hunter of 45 kg is standing on ice fires a bullet of 100 gram with a velocity of 500 m/s by a gun of
5 kg. Find the recoil velocity of the hunter.
6. A machine gun has a mass of 30 kg. The machine gun fires 35 g bullets at the rate of 400 bullets per minute with a speed of 400 m/s. What force must be applied to the gun so that the gun is kept in position ?

### Objective Problems:

 1.(B) 2.(B) 3.(C) 4.(A) 5.(B) 6.(A) 7.(B) 8.(A) 9.(B) 10.(B)

#### Subjective Problems

1. The recoil velocity of gun with hunter is 1 m/s.
2. Required force F= 93.3 N