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Homework Help: Spring and ball problem

  1. Nov 9, 2008 #1
    1. The problem statement, all variables and given/known data

    A child's game consists of a block that attaches to a table with a suction cup, a spring connected to that block, a ball, and a launching ramp. The spring has a constant k. the ball has a mass m, and the ramp raises a height h. The spring is compressed a distance S in order to launch the ball. when the ball leaves the launching ramp its velocity makes and angle with respect to the horizontal.

    1 Calculate the velocity of the ball when its leaves the launching ramp (both the magnitude and the direction. Be sure to specify your coordinate system)

    2. The spring constant = 1000.0 N/m the spring compression is 4. cm the ball's mass is 55 g, the height of the ramp is 15 cm and the top of the table is 1.2 m above the floor. With what speed will the ball hit the floor?

    2. Relevant equations
    Delta y = Vft+1/2gt2

    3. The attempt at a solution

    I really do not have a clue where to start I have been thinking on how to solve it but all i have done is write down some equations that may be helpful but i really dont know if they are helpful in this problem. Can someone please help me? thanks
  2. jcsd
  3. Nov 9, 2008 #2
    Have you considered conservation of energy?
  4. Nov 9, 2008 #3
    yes i had that equation KEf+PEf=KEi+PEi

    so 1/2 mvf2 + mgh = 1/2 mvi2 + mgh

    so in this case masses cancel and i would have to solve for vf
  5. Nov 9, 2008 #4
    Sounds fine by me.
  6. Nov 9, 2008 #5
    ok well i know that 1/2mvi^2 = 0 and the mgh final should be 0 too

    in that case vf= square root of 2gh

    however i got stuck because i there is no value given for h is there a way i can find h or am i suppose to have another equation
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