A person standing at the edge of a cliff throws one rock straight up and another rock straight down at the same initial speed. The rock that was thrown __________ has less speed at impact.
A) upward
B) downward
C) Actually, each rock has the same speed just before impact.

Question

Quizplus · Accepted Answer

The initial speed of both rocks is the same, so they will reach the same height and have the same potential energy. As they fall back down, they will convert their potential energy into kinetic energy, but this process is reversible. Therefore, when they meet the ground, both rocks will have the same speed, regardless of whether they were thrown upward or downward.

A Person Standing at the Edge of a Cliff Throws