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Homework Help: Roller Coaster

  1. Oct 21, 2007 #1
    1. The problem statement, all variables and given/known data
    A cart starts from position 4 in the figure below with a velocity of 13 m/s to the left. Find the speed with which the cart reaches positions 1, 2, and 3. Neglect friction.

    speed at position 1 ___ m/s
    speed at position 2 ___ m/s
    speed at position 3 ___ m/s

    2. Relevant equations

    E_tot1 = E_tot2 = E_tot3 = E_tot4

    The total energy is kinetic energy plus potential energy
    E_tot = E_kin + E_pot

    E_pot = m * g * h
    with m the mass of the cart, g the gravitational constant of Earth (g=9.81m/s^2) and h the height.

    E_kin = 1/2 * m * v^2

    3. The attempt at a solution

    I attempted to do this problem and I cannot figure out how to solve for any of them if I am not given the mass of the cart.
  2. jcsd
  3. Oct 21, 2007 #2


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    Homework Helper

    You shouldn't need the mass, since it will be common to each term and you will be able to cancel it out.
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