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Question
A ball is given a speed v on a rough horizontal surface. The ball travels through a distance l on the surface and stops. What is the work done by the kinetic friction?
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Solution
Work done by the kinetic friction is equal to the change in kinetic energy of the ball.
∴ Work done by the kinetic friction = \[ K_f - K_i = 0 - \frac{1}{2}\text{ mv }^2\]
=\[- \frac{1}{2}\text{ mv }^2\]
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