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Question
A block of mass 2 kg kept at rest on an inclined plane of inclination 37° is pulled up the plane by applying a constant force of 20 N parallel to the incline. The force acts for one second. Find the work done by the force of gravity in that one second if the work done by the applied force is 40 J.
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Solution
If \[W = 40 J\]
\[S = \frac{W}{F} = \frac{40}{20} = 2 \text{ m }\]
\[h = 2 \sin 37^\circ= 1 . 2 \text{ m } \]
So, work done
\[\text{ W = - mgh } \]
\[ = - 20 \times 1 . 2 = - 24 J\]
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