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Homework Help: Impulse problem

  1. Apr 28, 2008 #1
    1. The problem statement, all variables and given/known data
    A ball of mass .110 kg is dropped from rest from a height of 1.25 m. It rebounds from the floor to reach a height of .800 m. What impulse was given to the ball by the floor?

    2. Relevant equations


    3. The attempt at a solution

    Could someone please tell me if this is the correct formula?

    Thank you very much
  2. jcsd
  3. Apr 28, 2008 #2
    Hi chocolatelover! Both of your equations look right but need some minor tweaking.

    For starters (I have no clue why, but...) the symbol for impulse is a capitol J.

    So J = Δp for instance.

    Your first equation should be extended a bit more.

    J = ΣFΔt would give you an approximation for impulse however if you wanted the exact value of J you would need to make Δt -> 0, and sum up an infinite number tiny bits force.

    A more concrete definition would be [tex]J = \int_{t_i}^{t_f}{F dt}[/tex]
  4. Apr 28, 2008 #3
    Thank you very much

    Does this look right?
    integral from 1.25 to .800 (.110kg)(9.8m/s^2)dt


    Thank you very much
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