Legend

 W = work F = force d = distance KE = kinetic energy PE = potential energy v = velocity a = acceleration h = height
The higher this mountain climber climbs, the greater his gravitation PE will be relative to the ground.

Gravitational Potential Energy

 When a person climbs up a ladder, he does work to overcome the downward pull of gravity.  This work corresponds to a change in energy, and this is the gravitational PE.   Although he stays motionless, high on the ladder, W = PE.   That work equals the product of the force he exerts and the vertical height through which he ascends, h. Thus, PE = Fg h Given that the person has a mass m, we can write: PE = mg h = mg (hf-hi) Work results when there is a change in PE in the object.  Thus, Wnet = PE = mg (hf-hi) For simplicity's sake, we limit our activities to the Earth and assume g is constant.  PE, like KE is a relative quantity; even the idea of "height" is relative.  We say that the height at some level is zero and take the PE with respect to that level, since we're only concerned only with the changes in PE due to changes in altitude, which then removes the need to deal with the zero-reference level.  This results in the equation: PE = mgh
 Potential Energy Mechanical Energy

 created by Will Kuo and Stan Watterson thinkquest participants  team 25844 ©1999 Eloquent Logic. All rights reserved.