## Summary

Work is force multiplied by distance and has units of

J = joule = N-m Work is the component of the force in the direction of the displacement, multiplied by the displacement,

or

Energy is the ability to do work. You may think of energy as "stored up work";

KE = (^{1}/_{2}) m v^{2}

PE_{g}= m g h

PE_{el}= (^{1}/_{2}) k x^{2}We encounter many situations or many systems for which the

total energyremainsconstant. We describe this by sayingEnergy is conserved.

E = PE + KE

E = constant

PE + KE = constant

E _{i}= E_{f}

PE _{i}+ KE_{i}= PE_{f}+ KE_{f}(c) 2002, Doug Davis; all rights reserved

More ExamplesHomeworkReturn to ToC, Work and Energy