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Impulse-Momentum Problems

  1. Jan 31, 2009 #1

    1. A bullet with a mass of 0.0050kg and moving with a speed of 400 m/s penetrates a distance of 0.08m into a wooden block firmly attached to the earth. Assume that the force that stops it is constant.

    Compute for:
    a) The acceleration of the bullet
    b) The accelerating force
    c) The time of the acceleration
    d) The impulse of the force

    2. A baseball has a mass of 0.200kg.
    a) If the velocity of a pitched ball has a magnitude of 35m/s in the opposite direction, find the change in momentum of the ball and the impulse applied to it by the bat.
    b) If the ball remains in contact with the bat for 2.0x10^-3 sec, find the average force applied by the bat.

    3.) A ball with a mass of 0.40kg is thrown against a brick wall. It hits the wall moving horizontally to the left at 30m/s and it rebounds horizontally to the right at 20 m/s. Find the impulse of the force exerted on the ball by the wall. If the during the impact for 0.010sec, find the average force on the ball during the impact.

    F = ma
    a = v2-v1/t2-t1

    I really don't have an idea how to solve this problems. Please help me. :cry:
  2. jcsd
  3. Jan 31, 2009 #2


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    What is the relation between the initial velocity, final velocity and the dispalcemect?
    What is the work done by the bullet on the wooden block?
    what is the formula for momentum?
  4. Jan 31, 2009 #3
    1. I really don't know
    2. It is not given
    3. The formula for momentum is p = mv..
  5. Jan 31, 2009 #4


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    1. v^2 -u^2 = 2as
    2.Work done by the bullet = F*s = loss of kinetic energy of the bullet = 1/2mv^2
  6. Feb 1, 2009 #5
    v^2-u^2=2as?? I can't apply it since I don't have initial and final velocity.. OMG! please somebody help. I need this in three hours.
    Last edited: Feb 1, 2009
  7. Feb 1, 2009 #6


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    Initial velocity of the bullet is 400m/s. Finally it stops in the block. So the final velocity =0. s = 0.08 m.
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