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

Options

A. 23 J
B. 32 J
C. zero
D. can't be obtained

Answer

B

Explanation

`W=intvec(F).dvec(s)=int(3hati+5hatj).(4t dt hati) =int_(0)^(2) 12 t^(2) dt =(12[t^(3)]_(0)^(2))/3=32 J`