A 20.0-kg rock is dropped and hits the ground at a speed of 90.0 m/s. Calculate the rock's gravitational potential energy before it was dropped. (Ignore the effects of friction.)

Question

Physics

Audrina Armstrong

16 September, 17:44

A 20.0-kg rock is dropped and hits the ground at a speed of 90.0 m/s. Calculate the rock's gravitational potential energy before it was dropped. (Ignore the effects of friction.)

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Answers (1)

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Devin Kelley · Answer 1

GPE=81000J or 81kJ

Explanation

Potential Energy = mgh = 20 x 9.8 x?

To find H use one of the equation of motion

= [ (90) ^2 - 0 ] / 2 (9.8)

Potential Energy = mgh = 20 x 9.8 x 8100 / 2 (9.8) = 81000 J