Question

A force of (6 i + 2 j - 15 k ) N acts on a body of mass 5 kg to displace it along positive x axis through 2m .What is the work done in the process?

Answer 1

Answer is given in the pic.

Answer 2

Given : A force of (6i + 2j - 15k) N acts on a body of mass 5 kg to displace it along positive x - axis through 2 m.

To find : The work done in the process.

solution : force acts on the body, F = 6i + 2j - 15k

displacement of the body due to acting of force on it, s = 2 i

[ as body displaced along positive x - axis so in vector form displacement = 2i ]

we know, work done is the dot product of force and displacement.

so, W = F.s

= (6i + 2j - 15k).(2i)

= 6 × 2 + 2 × 0 - 15 × 0

= 12 J

Therefore the work done in the process is 12 J.