Final answer:
Energy is the capacity to do work. Work can be done on another object or on itself depending on the situation. Kinetic energy represents work done on an object and potential energy represents the energy stored in an object that can be converted into kinetic energy.
Step-by-step explanation:
Energy is defined as the capacity to do work. When an object is in motion, there is energy associated with that object because moving objects are capable of enacting a change, or doing work. Work can be done on another object or on itself, depending on the situation.
For example, if an object has kinetic energy, it means that work has been done on that object to give it that energy. This could be work done by a force acting on the object or work done by the object itself. The object can then use this kinetic energy to do work when it collides with another object.
Similarly, potential energy refers to the energy stored in an object. If a body has potential energy, it means that the object can convert that potential energy into kinetic energy when set free. This conversion of energy allows the object to do work.