A partical moves from a point `(-2hati + 5hatj)` to `(4hati + 3hatj)` when a force of (4hati + 3hatj) N` is applied . How much work has been done by the force?

Options

A. 8J
B. 11J
C. 5J
D. 2J

Answer

c

Explanation

(c ) Position vectors of the particles are `r_(1)=12hati+5hatj "and" r^(2)=4hatj +3hatk`
`therefore`Displacement of the particles, `Deltas=r_(2)-r_(1)`
`=4hatj +3hatk-(-2hati+5hatj)=2hati-hatj+3hatk`
Force on the particle ,`F=4hati +3hatj` N
`therefore` work done, `W=F.Deltas=(4hati+3hatj).(2hati-hatj+3hatk)`
`=8-35J`