Question

A water balloon was dropped from a high window and struck its target 1.1 seconds later. If the balloon left the person's hand at -5.0 m/sec, what was its velocity on impact?

Answer 1

The acceleration of gravity on Earth is 9.8 meters per second every second.  So
in 1.1 second of falling, an object gains (9.8 x 1.1) = 10.78 meters per second of
downward speed.

The balloon was already falling at 5 m/sec when the time began, and it gained
another 10.78 m/sec on the way.  So at the end of 1.1 second, its downward
speed was (5.0 + 10.78) = 15.78 m/sec.

Its velocity was 15.78 m/sec downward.