Explain that a change in gravitational potential energy is related to work done.
• Potential Energy is energy that is "stored" which can be converted into other forms of energy.
• Gravitational potential energy (GPE) is the energy of a mass due to its position within a gravitational field.
• \$e.g.\$ If a ball is placed atop a cliff, it will have the stored energy.
• Keep in mind that GPE is equivalent to work done in moving something to a point.
• W = Fs:
• W is work done(J)
• F is force applied(N)
• s is displacement(m)
• From this equation, we can say that, if we take the Earth's surface as the point of 0 GPE, we can find GPE using:
• GPE = mgh
• m is the mass of the object(kg)
• g is the gravitational acceleration of Earth(\$9.8 ms^{-2}\$)
• h is the vertical distance between the object and the Earth's surface(m)
• Note that this equation can work with other planets as well, obviously switching the value of \$9.8 ms^{-2}\$ to whatever the other planet's gravitational acceleration is.

--Richard Lou

page revision: 1, last edited: 29 Dec 2010 07:36