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Homework Help: Uniform Acceleration

  1. Feb 26, 2008 #1
    1. The problem statement, all variables and given/known data
    After uniformly accelerating his arm for 0.0500 s, a pitcher releases a baseball of weight 1.40 N with a velocity of 37.0 m/s horizontally forward. The ball starts from rest. (Assume that horizontally forward and upward are positive.)

    2. Relevant equations

    a)Through what distance does the ball accelerate before its release?

    b)What force does the pitcher

    3. The attempt at a solution

    I got part of part b What force does the pitcher ___Ni + 1.4Nj

    I really just need the equation to find part a.
  2. jcsd
  3. Feb 26, 2008 #2


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    [tex]v = a t[/itex]
    ring a bell? Can you apply that here?

    Also, the phrases "... with a velocity of 37.0 m/s horizontally forward." and "The ball starts from rest. " sound a bit contradictory to me (I assume they mean: it starts from rest, then the pitcher accelerates it, and when he lets go, it has a(n instantaneous) velocity of 37.0 m/s).
  4. Feb 26, 2008 #3
    I tried that but when I input the answer into the site it says it's wrong.
  5. Feb 26, 2008 #4

    Doc Al

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    Staff: Mentor

    What did you try? You need to find the distance it traveled during its acceleration. Start by finding the average speed.
  6. Feb 26, 2008 #5
    I think what compuchip gave you was the final velocity, after the release. From there you can find the acceleration, having the duration (time) of acceleration. then relating that final result to the change in position in the x direction using your kinematic equations to represent mathematically what is going on physically. Having just the equation never really helped me understand how to use them or when to use them.
  7. Feb 26, 2008 #6
    Ok I understood what you guys said and got part a but I'm still sort of confused about part b, the first part of it.
  8. Feb 26, 2008 #7

    Doc Al

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    Staff: Mentor

    Apply Newton's 2nd law.
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