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A body of mass `6kg` is under a force which causes displacement in it given by `S= (t^(2))/(4)` maters where `t` is time . The work done by the force in `2` sec isA. `12 J`B. `9 J`C. `6J`D. `3 J` |
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Answer» Correct Answer - C `s = (t^(2))/(4) :. Dx = (1)/(2) dt` `F = ma = (md^(2)s)/(dt^(2)) = (6d^(2))/(dt^(2)) [(t^(2))/(4)] = 3N` Now `W = int _(0)^(2) F ds = int_(0)^(2) 3 (t)/(2)dt = (3)/(2) [(t^(2))/(2)]_(0)^(2) = (3)/(4) [(2)^(2) - (0)^(2)] = 3 J` |
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