Question

A body is desplaced from origin to `(2m, 4m)` under the following two forces:
(a) `F=(2^hati + 6^hatj)N`, a constant force
(b) `F(2x^hati + 3y^(2)hatj)N`
Find word done by the given forces in both cases.

Answer 1

Correct Answer - B
(a) `F=(2hati + 6hatj)N`
`dr=(dxhati + dyhatj)`
`:. fdr= 2 dx + 6 dy`
`W =int_((0.0))^((2m.4m))F.dr = int_((0.0))^((2m.4m))(2dx + 6dy)`
`=[2x + 6y]_(0,0)^(2m,4m) =(2xx2 + 6xx4)`
`=28J`