Question

A water balloon was dropped from a high window and struck its target 2 seconds later. If the balloon left the person’s hand at –5.0 meters per second, what was its velocity on impact?

Answer 1

The acceleration of gravity is 9.8 m/s. So in 2 s of falling, an object gains $(9.8\times 2) = 19.6 \;m/s$ of downward speed.

The balloon was already falling at 5 m/s when the time began, and it gained another 19.6 m/s on the way. So at the end of 2 seconds, its downward speed was $(5.0 + 19.6) = 24.6 \;m/s$ .