Question

A particle acted upon by constant forces `4hati +hatj- 4 hatk` and `3hati + hatj - hatk` is displacment from the point `hati+ 2hatj+ hatk` to point `5hati + 4hatj +hatk`.Total work done by the forces in SI unit is :
A. 20
B. 40
C. 50
D. 30

Answer 1

Correct Answer - B
`vecF_(1) = 4hati + hatj - 3hatj" "and" "vecF_(2) = 3hati + hatj - hatk`
`vecF_("net")= 7hati + 2hatj - 4hatk`
`vecd= (5hati +4hatj- 3hatk)- (hati + 2hatj-hatk)`
`vecd=4hati + 2hatj-2hatk`
`W= vecF_("net")`. `Vecd = 28+ 4 + 8 = 40` unit