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Question
A body is being raised to a height h from the surface of earth. What is the sign of work done by applied force?
Solution
Force is applied to the body to lift it in an upward direction and displacement of the body is also in the upward direction, therefore, the angle between the applied force and displacement is θ = 0°.
∴ Work done by the applied force
W = Fs cos θ = Fs cos 0° = Fs .....(∵ cos 0° = 1)
i.e., W = Positive
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