1) A proton (mass 1 u) travelling with velocity +0.100 c collides elastically head-on with a helium nucleus (mass 4 u) travelling with velocity −0.050 c.

What are the velocities of each particle after the collision?

2) A trolley X of total mass 0.50 kg and speed 6.0 m s⁻¹ approaches, head-on, another trolley Y of total mass 0.60 kg and speed 5.0 m s⁻¹ moving in the same direction along a level track. The collision is elastic with each trolley having a magnet with the like poles facing each other as shown below.

At some instant during the collision, X is at rest. The speed of Y then is

3) An object of mass 1.5 kg is sliding with a velocity of 3.0 m s⁻¹ on a frictionless surface towards another object which is stationary and has a mass of 2.0 kg. This head-on collision is completely inelastic (the two objects are stuck together). If the duration of the collision is 0.050 s, the average force that is exerted between the objects during the collision is

4) Two equal masses X and Y are moving towards each other on a frictionless air track as shown. The masses make an elastic collision.

Which row gives possible velocities for the two masses after the collision?

5) The diagram shows the masses and velocities of two trolleys about to collide.

After the impact they move off together. What is the total kinetic energy of the trolleys after the collision?