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Conservative forces and Mechanical Energy

  1. Oct 16, 2012 #1
    1. A 750-kg automobile is moving at 20.0 m/s at a height
    of 5.0 m above the bottom of a hill when it runs out of
    gasoline. The car coasts down the hill and then continues
    coasting up the other side until it comes to rest.
    Ignoring frictional forces and air resistance, what is the
    value of h, the highest position the car reaches above
    the bottom of the hill?a




    2. E1=E2 or K1 + U1 = K2 + U2



    3. 1/2mv2+mgy=1/2mv2+mgy

    1/2(750kg)(20m/s)2+(750kg)(9.8m/s2)(5m)=1/2(750kg)(0m/s)2+(750kg)(9.8m/s2)(Y)

    I got y=25.41m or 25m with correct sig figs is that correct?
     
  2. jcsd
  3. Oct 16, 2012 #2

    BruceW

    User Avatar
    Homework Helper

    looks good to me. nice work. You could put in another sig fig in your answer, but I guess it can't be bad to over-estimate the error.
     
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