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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. Show that the work done by the applied force does not exceed 40 J.
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Solution
Given:
\[\text{ Mass of the block, m = 2 kg } \]
\[\theta = 37^\circ\]
\[\text{ Force on the block, F = 20 N } \]
From the above figure,
\[F = \left( 2g \sin \theta \right) + ma\]
\[ \Rightarrow a = \frac{20 - 20 \sin \theta}{2} = 4 \text{ m/ s}^2 \]
\[s = ut + \frac{1}{2}a t^2 = 2 m\]
\[\text{ So, work done } \]
\[W = FS = 20 \times 2 = 40 J\]
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