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WHy is kinetic PE assigned K, instead of U_k?

  1. Oct 30, 2015 #1
    Im confused about the different letters assigned to energy (in intro physics). SO far Ive learned about
    gravitational potential energy (U)
    Elastic potential energy (U)
    electric potential energy (U)
    and kinetic energy (K)

    How do we differentiate between all the different trypes of energy? Why dont they include like a U_g for GPE and maybe a E_e for elastic PE, etc? Also why use a "K" for KPE instead of U_k?

    As I understand it energy is usually referred to with leter U, maybe cuz its all in same units so must have same letter??

    thanks for any help
  2. jcsd
  3. Oct 30, 2015 #2


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    What letter you use to denote something is completely meaningless and only a matter of convention. The letter U is commonly used to denote potential energy regardless of origin. Kinetic energy is not a form of potential energy, common letters used to denote it include K and T.
  4. Oct 31, 2015 #3
    Absolutely, and the fact of the matter is, there are a lot more concepts than letters, so it is indeed always important not to be bothered by which letter is used to denote which concept. Concentrate on the name (gravitational potential energy, kinetic energy, etc) and not on the symbol.
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