Work

When a force moves an object work is done on the object and energy is converted from one form to another. The units for work are Joule (J).

Work done = force (F) x displacement (s) = force x displacement in the direction of the force Work done = Fs

Force and displacement are vectors but work is a scalar. If the force is applied at an angle q to the rails the truck has a displacement s along the rails but the truck moves a distance scos q in the direction of the force F.

In this case the work done on the truck is Fs[cos q].