Physics (AS & A Level) · May / June 2023 · Paper 12 · Question 10

Two balls, X and Y, approach each other along the same straight line and collide. The collision is perfectly elastic. Their initial speeds are u_X and u_Y respectively. After the collision they move apart with speeds v_X and v_Y respectively. Their directions are shown. Which equation is correct?

1. Au_X + u_Y = v_X + v_Y
2. Bu_X + u_Y = v_X – v_Y
3. Cu_X – u_Y = v_X + v_Y
4. Du_X – u_Y = v_X – v_Y

As printed in the paper