Question

A small parachute is dropped from a cliff. it falls at a constant speed rate 2 m/s. A small rock is dropped 20.0 seconds later. how far will the rock drop before it passes the parachute?

Answer 1

We want the distances fallen to be equal. The parachute falls for 20 seconds more than the rock:

2(t+20) = 4.9t^2
4.9t^2 - 2t - 40 = 0
t = 3.07

so, after about 3 seconds, the rock either passes the chute, or it hits it.