A force`F=(3thati + 5hatj)N` acts on a body due to which its displacement varies as `S=(2t^(2)hat-5hatj)m`. Work done by these force in `2 s` is .

Options

A. `32 J`
B. `24 J`
C. `46 J`
D. `20 J`

Answer

B

Explanation

`v=(dS)/(dt) =(4t)hati`
`P=F.v =12 t^(2)`
`:. W =int_(0)^(2) Pdt =int_(0)^(2)(12) t^(2)dt`
=24 J`.