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Homework Help: Collision and Kinetic Energy Problem

  1. Mar 5, 2013 #1
    A ball, which has a mass of m1 = 2.50 kg., is moving with a velocity of 8.00 m/s at an angle of 25.0˚ South of West. It collides with a second ball, which has a mass of m1 = 1.20 kg., which is moving with a velocity of 4.75 m/s at an angle of 61.0˚ North of West. They stick together and move as one.
    What will be the final velocity v3 of the balls after the collision?
    How much kinetic energy was lost in this inelastic collision?

    I attached a picture of my work
    I'm not sure if my work is right.

    Also, for the kinetic part, would I just use (1/2)mv^2 = (1/2)mv^2 - Wnc?


    Attached Files:

  2. jcsd
  3. Mar 5, 2013 #2


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    Overall, looks good. But I think you dropped out the factor of 3.7 during the calculation of the y-component which has thrown off your answer for the angle. Also, it's a good idea to state your angle clearly in terms of "south of east" or whatever.
    Last edited: Mar 5, 2013
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