Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: In what unit do you measure potential energy?

  1. Nov 4, 2005 #1
  2. jcsd
  3. Nov 4, 2005 #2


    User Avatar
    Homework Helper

    What grade are you in?
  4. Nov 4, 2005 #3
    You answered this question yourself in your "help " thread
  5. Nov 4, 2005 #4
    A really cool thing about units: If you know a formula for something, then you know the units, in a way. For example, you know that

    Force = Mass x Acceleration

    If the units of Mass are kg and the units of acceleration are m/s^2, then the units of force are kg x m/s^2. Force is an important concept, and so we have a special name for it: Newton. Still, kg x m/s^2 is also correct, although you may lose points for using it.

    A really cool thing about energy: Imagine a bottle with a wind-up toy in it, so well sealed and isolated that nothing could get in or go out. No matter, no energy, nothing. The total energy in the bottle: kinetic + potential + whatever will never change. At first, there's a lot of potential energy in the wind-up toy's spring, but little kinetic energy, because the car is still. Later, the spring winds down, and there is little potential energy, but plenty of kinetic energy, because the car is moving. The sum of the energy doesn't change though. Think about it. You can add up the different forms of energy. That means that they have the same units. No special units for kinetic energy, potential energy, whatever energy. Just one unit for all kinds of energy...

    Hope this helps...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook