Question

A body of mass 4 kg is acted upon by a force.The position of body with respect to time t is denoted by x=t^4/4.The work done by the force in first three seconds can be expressed in S.I. system as
(a) 1458 J
(b) 729 J
(c) 54 J
(d) 27 J
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Answer 1

I think so (a) part .

I hope it will help full to you

Answer 2

Answer:

$ln(dw) = ln(f.dx) \\ ln(dw) = ln(12 {t}^{2} . {t}^{3} ) dt \\ = \frac{12}{6} . {3}^{6} \\ = 1458$

acceleratiom changes with time hence we have to integrate the work done