InterviewSolution
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InterviewSolution
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A body is being raised to a height h from the surface of earth. What is the sign of work done by (a) applied force (b) gravitational force ? |
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Answer» (a) Force is applied on the body to lift it in upward direction and displacement of the body is also in upward direction, therefore angle between the applied force and displacement is `theta==0^(@)` Work done by the applied force `" " "W=Fs cos theta=Fs cos 0^(@)=Fs (therefore cos 0^(@)=1)` `i.e. " " "W=Positive"` (b) The gravitational force acts inm download direction and displacement in upward direction therefore angle between them is `theta=180^(@)` Work done by the gravitional force W=Fs cos `180^(@)=-Fs` |
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