Physics (AS & A Level) · May / June 2021 · Paper 12 · Question 10

A nitrogen molecule P travelling at a speed of 320 m s⁻¹ in a vacuum collides with a stationary nitrogen molecule Q. After the collision, P travels at a velocity of 180 m s⁻¹ at an angle of 55° to its original path. Q travels in a direction at an angle of 34° to the initial path of P. [diagram: before collision P moving at 320 m s⁻¹ towards stationary Q; after collision P at 180 m s⁻¹ at 55° and Q at velocity v at 34°] Assume that there are no external forces acting on the molecules. What is the magnitude v of the velocity of Q after the collision?

1. A120 m s⁻¹
2. B140 m s⁻¹
3. C180 m s⁻¹
4. D260 m s⁻¹

As printed in the paper