Occurs when a force causes an object to be displaced. The work done on an object is equal to the product of the on the object and its displacement. is the ability to do work. The theorem states that the work done on a system is equivalent to the change in the energy of the system. Without work is not done to an object; therefore, the object will not have any energy since the object is not moving. Three things to consider when determining the work done on an object are force, and the cause of the displacement by force.