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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?
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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