Question

A particle moves from point P(1,2,3) to (2,1,4) under the action of a constant force `F=(2hati+hatj+hatk)N`. Work done by the force is
A. 2 J
B. 4 J
C. 16 J
D. 8 J

Answer 1

Correct Answer - A
(a) Particle moves from P(1,2,3) to (2,1,4)
`:. "Distance" PQ =(2hati+hatj+4hatk)-(hati+2hat+3hatk)`
`d=PQ=(hati-hatj+hatk)`
Force `F=(2hati+hatj+hatk)`
Work done by the force
`W=F.d=(2hati+hatj+hatk).(hati-hatj+hatk)=2-1+1=2 J`