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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


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    Science Advisor
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    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:)
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