Projectile: Textbook solutions

Question 1:

A vertical mast is 32 m high. Two balls P and Q are projected at the same time. Ball P is projected horizontally from the top of the mast with speed 18 ms^-1. Ball Q is projected from the bottom of the mast with speed 30 ms^-1 at an angle α above the horizontal. The balls move freely under gravity in the same vertical plane and collide in mid-air. By considering the horizontal motion of each ball,

a) Prove that cos α = (3/5)

b) Find the time which elapses between the instant when the balls are projected and the instant when they collide.

Solution for Question 1