Work: force, displacement, Energy, Joules

By definition, work is a force that acts through a distance. Mathematically work is defined by the equation W = f x d. Anytime a __force__ moves an object through a __distance__ energy is transferred to the object and __work__ is done. Look at diagram "A" below. This diagram shows a 4kg ball being rolled up the incline. When a force is applied to move the ball up the incline, work is done on the ball, and as the ball gains energy. It is interesting to note that the work done on the ball is in the direction the ball is lifted against the force of gravity, up. The fact that the ball is being moved up an incline is irrelevant, the work is done vertically, against the force of gravity.

Diagram A

Here is a slightly different situation. Diagram "B" illustrates a situation in which the work is being done horizontally. The is work done moving the cart a horizontal distance of 50m by applying a force of 30N. The work done by Moe while pulling the cart is 1500J.

Diagram B