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Homework Help: Need Help with Momentum and Impulse? Need some one smart

  1. Nov 27, 2008 #1
    Need Help with Momentum and Impulse?!?! Need some one smart......

    The only formulas that were provided were

    1. I =Δp
    2. mΔv
    3. I=FΔt
    4. KE= 1/2 mv^2
    5. PE= mgΔh
    6. ΔPE= ΔKE
    7. W= F*D
    8. W= ΔKE

    Momentum Before Collision = Momentum After Collision

    9. m`av`a + m`bv`b = m`av`a + m`bv`b Elastic Collision
    10. m`av`a + m`bv`b = m`av`b(v) inelastic collision

    The little apostrophe are for subscripts, e.g. m`a, meaning "m" is normal, but the a is a subscript.


    Questions
    1. A tennis ball may leave the racket of a top player on the serve with a speed of 65 m/s. If the ball's ,*** is .06 kg and it is in contact with the rackt for .03 secs, what is the average force on the ball?

    2. A .145 kg basball pitched at 39 m/s is hit on a horzontal line drive straight back towards the pitcher at 52 m/s. If the contact time betwween bat and ball is 1.00 E-3 sec, calculate the average force between the bat and ball contact.
     
  2. jcsd
  3. Nov 27, 2008 #2
    Re: Need Help with Momentum and Impulse?!?! Need some one smart......

    1) You know the ball starts off at rest, and is then given a hit, which leads to a change in momentum. Impulse is a change in momentum; substitute and use that with the impulse formula to solve for force.

    2)Yet again, solve for the change in momentum. Once found, set equal to I=FΔt
     
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