1

v A body moving with speed v collides v 2 elastically with another body travelling in v the opposite direction with speed . 2 Which row in the table below correctly gives the relative velocity of approach and the relative velocity of separation of the two bodies? [1]

Relative velocity of approach A B C D

Relative velocity of separation

v 2 v 2 3v 2 3v 2

v 2 3v 2 v 2 3v 2

2

A body of mass m travels with a velocity 3v and collides with another particle of mass 2m which is initially stationary. After the collision, the two particles move with the same velocity. Which row in the table gives the final velocity of the two particles and the loss in kinetic energy during the collision? [1] A B C D Final velocity v v 1.5 v 1.5 v Loss in kinetic energy mv2 3mv2 mv2 3mv2

3

In an inelastic collision which quantities are conserved?

A B C D

[1]

total kinetic energy and total momentum but not total energy total kinetic energy and total energy but not total momentum total momentum and total energy but not total kinetic energy total kinetic energy, total momentum and total energy [1]

4

A particle has momentum p1 at time t1 and momentum p2 at time t2. What is the average force acting on the particle between t1 and t2?

⎛ A ⎜ ⎜ ⎝ ⎛ B ⎜ ⎜ ⎝

p1 + p2 ⎞ ⎟ t1 + t2 ⎟ ⎠ p2 − p1 ⎞ ⎟ t 2 − t1 ⎟ ⎠

⎛p p ⎞ C 0.5 ⎜ 1 + 2 ⎟ ⎜t ⎟ ⎝ 1 t2 ⎠ ⎛p p ⎞ D 0.5 ⎜ 2 + 1 ⎟ ⎜t t1 ⎟ ⎝ 2 ⎠

AS and A Level Physics

Original material © Cambridge University Press 2010

1

6 Worksheet (AS)

5

What is a correct statement of the principle of conservation of momentum? A B C D

[1]

in an inelastic collision the total kinetic energy and momentum are constant in any collision the total momentum of an isolated system is constant in any isolated system the force on a body equals the rate of change of momentum momentum is constant when mass and velocity are constant

6

A bumper-car collides at right angles with a metal barrier and rebounds at the same speed. A student suggests that the change in momentum of the car is zero. Explain why the student is wrong. Each diagram shows a 2.0 kg object before and after a collision. Calculate the change in momentum of the object in each case.

[2]

7

a

[2]

b

[2]

c

[2]

8

A cannon of mass 850 kg fires a 20 kg shell at a velocity of 180 m s−1. a Calculate the final momentum of the shell. b What is the magnitude of the momentum of the cannon immediately after the shell is fired? (You may assume that the cannon is initially at rest.) c Calculate the recoil velocity V of the cannon.

[2] [2] [3]

9

A car of mass 900 kg travelling at a velocity of 28 m s−1 makes a head-on collision with a stationary van of mass 1500 kg. The car and the van get tangled together. a Calculate the combined speed of the tangled vehicles immediately after the collision. b Calculate the initial kinetic energy of the car and the final kinetic energy of the tangled car and van immediately after the collision. c Use your answer to b to explain whether the collision is elastic or inelastic.

[4] [3] [1]

AS and A Level Physics

Original material © Cambridge University Press 2010

2

6 Worksheet (AS)

10 The diagram below shows the initial state of two trolleys A and B before colliding and the final state immediately after the collision.

Calculate the final velocity v of trolley B.

[4]

11 The diagram shows two toy trains T and R held in place on a level track against the force exerted by a compressed spring.

When the trains are released, R moves to the right at a speed of 3.8 m s−1. The spring takes 0.25 s to uncoil to its natural length. a Calculate the velocity of train T. b Calculate the average force exerted by the spring on each train. 12 A ball of mass 210 g moving at a speed of 23 m s−1 hits a wall at right angles and rebounds at the same speed. The ball is in contact with the wall for 0.31 s. a Calculate the change in momentum of...