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## a 5.0 kg ball is dropped from a 2.5 m high window. what is the velocity of the ball just before it hits the ground?

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## Answers ( )

Answer:Approximately .

Assumption: the ball dropped with no initial velocity, and that the air resistance on this ball is negligible.

Explanation:Assume the air resistance on the ball is negligible. Because of gravity, the ball should accelerate downwards at a constant near the surface of the earth.

For an object that is accelerating constantly,

,

where

In this case, is the same as the change in the ball’s height: . By assumption, this ball was dropped with no initial velocity. As a result, . Since the ball is accelerating due to gravity, .

.

In this case, would be the velocity of the ball just before it hits the ground. Solve for

.

.