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Find Average Power Given Mass and Velocity

  1. May 27, 2012 #1
    During 12 s an engine increases the speed of a 1.5×103-kg vehicle from 13 m/s to 27 m/s. Assuming no losses, what average power is the engine producing?

    P = W/t
    W=FΔx
    W=ΔKE
    ΔKE=mvf2-mfi2

    I tried finding the change in kinetic energy to solve the problem, but it didn't work. I got 3.4E3 W. I'm really lost. I've never done a power problem given only velocity and mass.
     
  2. jcsd
  3. May 27, 2012 #2
    You aren't just given velocity and mass. You are given the initial and final velocities, along with the time. From this you can easily calculate the acceleration of the body.

    Now that you have acceleration, you also get the force. And displacement should be easy to calculate from the equations of motion. Should be pretty easy from here on...
     
  4. May 27, 2012 #3
    Thanks! And I realized my problem was that for some strange reason I was using 14 m/s as the final velocity instead of 27 m/s.
     
  5. May 27, 2012 #4
    Glad to be of help! :smile:
     
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