A ball is dropped from the top of a cliff. By the time it reaches the ground, all of its gravitational potential energy has been transferred into kinetic energy. If the ball is travelling at 20m/s when it hits the ground, what height was it dropped from? (Assume that the gravitational field strength is 10N/kg.)

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Physics

4 October, 12:25

A ball is dropped from the top of a cliff. By the time it reaches the ground, all of its gravitational potential energy has been transferred into kinetic energy. If the ball is travelling at 20m/s when it hits the ground, what height was it dropped from? (Assume that the gravitational field strength is 10N/kg.)

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Antony Mcbride · Answer 1

20 m

Explanation:

Initial potential energy = final kinetic energy

mgh = 1/2 mv²

gh = 1/2 v²

h = v² / (2g)

Given v = 20 m/s and g = 10 m/s²:

h = (20 m/s) ² / (2 * 10 m/s²)

h = 20 m