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A force given by the relation F = 8t, acts on a body of mass 2 kg, initially at rest. Find the work done by this force on the body during first 2 seconds of its motionA. 64 JB. zeroC. `- 64 J`D. none of these |
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Answer» Correct Answer - A `F = 8t` `m (dv)/(dt) = 8t` `m underset(0)overset(v)int dv = 8 underset(0)overset(t)int t dt` `mv 4t^(2)` or `m = (dx)/(dt) = 4 t^(2)` `rArr dx = (4 t^(2))/(m) dt = 2t^(2) dt` `W = int Fdx = underset(0)overset(v)int (8 t xx 2 t^(2)) dt = 64 J` |
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