The energy associated with the position of an object in the field of a force. The first potential energy that we define is gravitational potential energy but potential energy can be defined for any conservative force and its associated field. A force for which the work done in moving an object from one place to another does not depend on the path taken from point A to point B . Gravity is such a force. A force for which work done depends on path taken as the force moves an object.
Friction is such a force.
The rate at which work is done. That is power is a measure of how much work is done by a source in each second . This raises the possibility that no work is done if there is no displacement and there is no work done if the force is perpendicular to the displacement . Since work defines energy the units of work are the units of energy. The restoring force exerted by a stretched or compressed spring is directly proportional to the amount the spring is distorted and applied in the opposite direction.