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Homework Help: Momentum/Impulse problems

  1. Oct 24, 2004 #1
    I need help with this problem.

    1) A 0.145kg baseball pitched at 39m/s is hit on a horizontal line drive straight back toward the pitcher at 52m/s. If the contact time between bat and ball is 1.00 X 10^-3s, calculate the average force between the ball and bat during contact.

    And for this problem I need to know if the answers I got were correct.

    2) A golf ball of mass .045kg is hit off the tee at a speed of 45m/s. The golf club was in contact with the ball for 5.0 X 10^-3s. Find (a) the impulse imparted to the golf ball, and (b) the average force excerted on the ball by the golf club.

    This is what I got.

    BTW The 5.0 X 10^-3 is my way of showing scientific notion on the computer.
    Impulse = 2.03
    Average Force = 406
     
  2. jcsd
  3. Oct 24, 2004 #2
    Your answers for the second question are correct but if you want to follow the rules of significant figures, round them to 2 significant figures only.
    If you can find the average force for the second question, i don't see why you çan't find for the first question.
     
  4. Oct 24, 2004 #3
    Well in the first question the ball is pitched to the batter, while in the second question the ball starts of stationary.
     
  5. Oct 24, 2004 #4
    well, what is the formula you use to find the average force in the second question ?
     
  6. Oct 24, 2004 #5
    Fnet = Tri P / Tri T

    The Tri being a triange which means P final minus P initial and P meaning Momentum with T meaning Time.
     
  7. Oct 25, 2004 #6
    [tex]F_{net}=m*\frac{v-u}{t}[/tex]
    v is the final velocity and u is the initial velocity of the baseball. the direction of v is opposite to the direction of u. Insert the appropriate sign after you have choosen your 1-D reference frame.
     
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