Graviational Potential Energy

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The Main Idea

Siimilar to potential energy caused by elastic potential, gravitational potential energy is caused by an object's position in a gravitational field relative to a chosen zero point.


A Mathematical Model

PE = mgh

  • m = the object's mass in kilograms
  • g = gravitational acceleration, 9.8 m/s^2 on earth
  • h = the object's height in meters from a chosen reference point

Examples

What is the potential energy of a 5kg object on top of a 20 meter structure?

  • PE = mgh
  • PE = (5 kg) * (20 m) * (9.8 m/s^2)
  • PE = 980 kg*m^2/s^2 = 980 J

Connectedness

Because of conservation of momentum, gravitational potential energy has many applications in physics, chemsistry, and several facets of engineering. For example, how fast will a ball hit the ground when dropped from a certain height? How much work is done by a tall waterfall? How high can you build a rollercoaster? Will roadrunner escape the perils of introductory physics (see video below)?

Video

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References

  • Matter & Interactions, Vol. II: Electric and Magnetic Interactions, 4nd Edition by R. Chabay & B. Sherwood (John Wiley & Sons 2015)
  • Hyperphysics: Gravitational Potential Energy, Georgia Southern University