Question

Work done by a force `F=(hati+2hatj+3hatk)` acting on a particle in displacing it from the point `r_(1)=hati+hatj+hatk` to the point `r_(2)=hati-hatj+hat2k` is
A. `-3 J`
B. `-1 J`
C. zero
D. 2 J

Answer 1

Correct Answer - B
(b) `W=F.s=F.(s_(2)-s_(1))`
`=(hati+2hatj+3hatk).[(hati-hatj+2hatk)-(hati+hatj+hatk)]`
`=(hati+2hatj+3hatk).(-2hatj+hatk)=-4+3=-1J`