At the top of a cliff 100 m high,Raoul throws a rock upward with velocity 20.0 m/s.How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?
A) 5.05 s
B) 3.76 s
C) 2.48 s
D) 1.78 s

Question

Quizplus · Accepted Answer

The first rock is thrown upward, reaching a maximum height before falling down. The total time for the first rock to hit the ground can be calculated using the kinematic equation. The second rock is dropped from rest, so its time to hit the ground is less. The difference in these times gives the delay needed for the second rock.

At the Top of a Cliff 100 M High,Raoul Throws