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Homework Help: Impulse of a ball

  1. Jun 13, 2010 #1
    1. The problem statement, all variables and given/known data
    A 0.150 kg ball is dropped 1.25m from rest. It rebounds to a height of 0.960m. What is the impulse given to the ball by the floor?


    2. Relevant equations
    I=[tex]\Delta[/tex]p and p=mv were the equations I was trying to use. I was pretty sure I should use F=ma since the only other thing that I know is acceleration due to gravity. I don't know anything about time so I ruled out [tex]\int[/tex][tex]\sum[/tex]Fdt.


    3. The attempt at a solution
     
  2. jcsd
  3. Jun 13, 2010 #2

    Doc Al

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    Good. So how can you figure out the velocity just before and just after it hits the floor?

    Hint: When the ball is in the air, it's just a projectile.
     
  4. Jun 13, 2010 #3

    kuruman

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    Using I = Δp is the correct approach. Can you find what v just before and just after the collision? If so, then you can find Δv and from this Δp.
     
  5. Jun 13, 2010 #4
    So can I use the kinematics equations? Since I don't know anything about time can I use vf2= vi2+2a (xf-xi) to find the velocity?
     
  6. Jun 13, 2010 #5

    Doc Al

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    Sounds good to me.
     
  7. Jun 13, 2010 #6
    thanks kindly to all!!
     
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