- compound machines: machines that combine two or more simple machines
- efficiency: a measure of how much useful work a machine can do
- kinetic energy: the energy that an object has because it is in motion
- mechanical advantage: the ratio between the output force and the input force in a machine
- mechanical energy: the sum of the potential energy and the kinetic energy in a system; the amount of work an object can do becaus of the object's kinetic and potential energies
- potential energy: the stored energy resulting from the relative positions of objects in a system
- power: the rate at which work is done, that is, how much work is done in a given amount of time
- simple machines: one of the six basic types of machines of which all other machines are composed
- work: the quantity of energy transferred by a force when it is applied to a body and causes that body to move in the direction of the force