Summarizing Gravitational Potential Energy

Summary

• Work done against gravity in lifting an object becomes potential energy of the object-Earth system.
• The change in gravitational potential energy, \(\Delta {\text{PE}}_{\text{g}}\), is \({\text{ΔPE}}_{g}=\text{mgh}\), with \(h\) being the increase in height and \(g\) the acceleration due to gravity.
• The gravitational potential energy of an object near Earth’s surface is due to its position in the mass-Earth system. Only differences in gravitational potential energy, \({\text{ΔPE}}_{g}\), have physical significance.
• As an object descends without friction, its gravitational potential energy changes into kinetic energy corresponding to increasing speed, so that \(\text{ΔKE}\text{= −}{\text{ΔPE}}_{\text{g}}\).

Glossary

gravitational potential energy

the energy an object has due to its position in a gravitational field