Question

A body constrained to move in the y direction is subjected to a force F= 2i + 15j + 6k N. The work done by this force in moving the body through a distance of 10m along v-axis is?

Answer 1

F= 2i +15j + 6k N
displacement, s= 10j m
work done, W = F.s
                       =(2i +15j + 6k ).10j
                       = 0 + 150 +0
                       = 150 N-m or Joule

Answer 2

Force =2i+15j+6k

Displacement =10

Work =force ×displacement

=2×i×10j+15×j×10j+6×k×10j (we know i×j=0,j×j=1,k×j=0)

=2×0×10+15×1×10+6×0×10

=0+150+0

=150j answer

I hope my answer is right