 µ IB | Momentum

10 quick questions

10 minutes maximum! (can you do it in 5?)

1-3. A 200 kg cannon initially at rest fires a cannonball of mass 2 kg at a velocity of 100 ms-1. 1. After firing, what is the momentum of the cannonball?

• A. 50 kg m s-1
• B. 100 kg m s-1
• C. 200 kg m s-1
• D. 400 kg m s-1

2. What is the total momentum of the system after firing?

• A. 0 kg m s-1
• B. 100 kg m s-1
• C. 200 kg m s-1
• D. 400 kg m s-1

3. What is the recoil velocity of the cannon?

• A. 200 m s-1
• B. 100 m s-1
• C. 2 m s-1
• D. 1 m s-1

4-6. Two 'trolleys' (blocks of wood on wheels) are collided together.

The trolleys have magnets on top so they stick together after the collision. Trolley A is moving at 3 m/s towards B, which is stationary. 4. What is the speed of both A+B (stuck together) after the collision?

• A. 100 kg m s-1
• B. 1.5 m s-1
• C. 1 m s-1
• D. 2 m s-1

5. What is the impulse of trolley A on Trolley B?

• A. 0 kg m s-1
• B. 12 kg m s-1
• C. 6 kg m s-1
• D. 4 kg m s-1

6. The collision of the trolleys is inelastic. This means that....

• A. momentum is not conserved.
• B. kinetic energy is not conserved.
• C. the elastic energy is not conserved.
• D. the total momentum after the collision is negative.

7. A particle of mass m is accelerated to a velocity v. The momentum of the particle is p and the kinetic energy is k.

A second particle of mass ½m has the same momentum, p. This means the kinetic energy will be...

• A. ¼ k
• B. ½ k
• C. 2 k
• D. 4 k

8-10. A basketball of mass m is thrown to the right at a wall with a velocity of v. It rebounds at the same speed, moving to the left. 8. What is the impulse acting on the ball during the impact?

• A. ½ mv
• B. mv
• C. ½ mv2
• D. 2 mv

9. If the force acting on the ball is constant, acting for a time t, the force will be given by... 10. Which answer correctly describes the type of collision with the wall and the direction of the force of the wall on the ball?

 collision direction of force on the ball A elastic to the left B elastic to the right C inelastic to the left D inelastic to the right