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Homework Help: Roller coaster prob.

  1. Dec 13, 2003 #1
    The mass of the coaster is 800 kg
    The lift hill is 18 m highabd it goes up the lift hill at 2.50 m/s
    The second hill is 5.5m high.

    Wants to know the speed at the top of the second hill.
    do i really care about the weight of the car?

    This is what i have so far

    PEtop1 +KEtop1 = KE bott
    2*9.80*18 +2.5^2 = v^2 bott
    V bott = 18.9 m/s

    second formula was
    Ke bott - Pe top1 = KE top 2
    18.9^2 - 2*9.80*5.5 = V^2 top 2

    Vtop 2 = 15.9 m/s and that is my final answer is that look right

    thanks
     
  2. jcsd
  3. Dec 13, 2003 #2
    Yep...answer looks right to me.
     
  4. Dec 13, 2003 #3
    thanks

    thanks hindi
     
  5. Dec 13, 2003 #4
    I believe the mass doesn't matter in this problem because the coaster is under constant acceleration for the whole run (gravity).
     
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