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Question
State the condition when the work done by a force is negative. Explain with the help of examples.
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Solution
If the displacement of the body is in the direction opposite to the force, then the work done is negative.
Hence, W = - F × S
For example, when a body moves on a surface, the force of friction between the body and the surface is in a direction opposite to the motion of the body, and so the work done by the force of friction is negative.
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