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

Total energy of an object.

  1. Oct 17, 2010 #1
    1. The problem statement, all variables and given/known data
    If a question asks to calculate total energy of an object that does have a horizontal velocity (constant, air resistance ignored), and it is at it's highest point so it's vertical velocity is zero.

    I need to know how you'd calculate the total energy of this object.

    Let's take mass as 5kg. And a highest point of 3m. Horizontal velocity of 2m/s. (I just made them up).


    2. Relevant equations
    Potential energy = mgΔh
    Kinetic energy = 0.5mv^2


    3. The attempt at a solution
    Pe= 5*9.81*3 = 147.15J
    Ke= 5*2^2= 20/2 = 10J

    10+147.15= 157.15J

    I was just wondering if I am not leaving anything out, or if I'm even doing it correct! Thanks
     
  2. jcsd
  3. Oct 19, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi Sixty3 :smile:

    (try using the X2 tag just above the Reply box :wink:)
    Yes, that's fine …

    at launch, and when on return to the ground, its KE is 157.15J.

    (btw, we normally put a capital 'E' in KE and PE :wink:)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook