A body of mass 3 kg is under a force causes a displacement in it, given by `S=t^(2)/3` (in metres). The work done by the force in 2 s is 

Options

A. 2J
B. 3.8J
C. 5.2J
D. 2.6 J

Answer

D

Explanation

`W = int_(t = 0)^(t = 2) F dS = int_(t = 0)^(t = 2)M ((d^2S)/(dt^2))((dS)/(dt)) dt`
`int_(t = 0)^(t = 2) 3(2/3)((2t)/(3)) dt = 4/3 int_(0)^(2) t dt = 2.6 J`