Question

A force 2i +5j-7k displaces a body of 1 kg from a point p(-2,1,-1) to a point q(4,3,-1).Find the work done on the body

Answer 1

W = F.s

force is 2i+5j-7k

displacement is q -p i.e. 4i +2i +3j-j +0k

6i+2j = s

w = ( 2i+5j-7k ) ( 6i + 2j )

W = 12 + 10

W =22 J