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2 years ago

3

A ball weighing 10 kg traveling at 1.4 m/s hits and rebounds back off a wall and now travels 1.4 m/s in the opposite direction.

What is the work done on it?

1 answer:

Marizza181 [45]2 years ago

4 0

<em>NO work is done on the ball.</em>

Its momentum changes, but its kinetic energy doesn't.

<u>Before it hits the wall:</u>

Momentum = m v = (10 kg) x (1.4 m/s) = +14 kg-m/s

Kinetic energy = (1/2)(m)(v²) = (1/2)(10kg)(1.4)² = 9.8 Joules

<u>After it hits the wall:</u>

Momentum = m v = (10 kg) x (-1.4 m/s) = -14 kg-m/s

Kinetic energy = (1/2)(m)(v²) = (1/2)(10kg)(-1.4)² = 9.8 Joules

No change in energy ==> no work done on the ball.

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Answer with Explanation:

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