Relative Speed of Falling Objects · PhysicsBowl 2018 #28
Physics · mechanics
Problem
At the top of a high cliff, a small rock is dropped from rest. A ball is launched straight downward with an initial speed of 36.0 m/s at a time of 2.10 s after the rock was dropped from the same cliff. When the ball has fallen 28.0 m further than the initially dropped rock, what is the speed of the ball relative to the rock?
(A) 15.0 m/s (B) 16.0 m/s (C) 20.0 m/s (D) 21.0 m/s (E) 36.0 m/s