1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How does cant made nor destroy law of energy work here

  1. Mar 1, 2016 #1
    imagen a ball of a kilogram is one meter above the surface of earth, no movement. its energy is
    but if you place it 9 meters higher it has a total of 1x9,81x10=98,1J and there is still no movement
    if energy can't be made or destroyed, where did the 89 J come from?
  2. jcsd
  3. Mar 1, 2016 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    From "you". You moved it higher, and thus, you did work onto the object against the gravitational field. This work that you did is equal to the potential energy gain of the object.

  4. Mar 1, 2016 #3
    i tried it out myself and yes
    W=m*g*d= 1*9,81*9=88,29J
    this plus the potetial energy i already had and you get
    thank you
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook