Question

Question #27f28

Answer 1

Dot product extracts the component of the force that is parallel / anti-parallel to the displacement vector.

Explanation:

Only the component of force that is parallel/anti-parallel to the displacement vector does the work. So work is defined as the product of the magnitude of displacement with the component of force parallel/anti-parallel with the displacement.

`dW \equiv vec F.vec (dr) = F_{||}dr = F\cos\theta.dr`