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Homework Help: Momentum in Two Directions

  1. Dec 5, 2007 #1
    So this is going to be very hard to explain without a diagram, so i will try to include one as best as i can.

    One object with mass 4 kg is traveling at 10 m/s. This object is in quadrant II of an x,y graph and is traveling toward the origin at 30 degrees above the negative x axis. The second object has mass 6 kg aand is traveling straight up the y axis. After the collision the first object (still with mass 4 kg) travels at 45 degrees below the negative x axis at a speed of 8 m/s. The object with mass 6 kg is now traveling at some angle above the positive x axis with some velocity. I have to find both the velocity and the direction this object is moving in

    This diagram shows how object 1 moves before (quadrant II) and after (Quadrant III)

    the 30 and 45 are the angles of path the object travels in relation to the negative x axis

    So object two with mass 6 kg and speed 8 m/s travels from below the x axis straight up along the y axis and impacts at the origin, then it travels diagonally right/upward into quadrant I

    any help would be greatly appreciated
    Last edited: Dec 5, 2007
  2. jcsd
  3. Dec 5, 2007 #2


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    Homework Helper

    Momentum in two directions.

    I think you have marked the axis wrongly. Interchange x and y letters.
    Now take the x-component two momentums before collision and after collision and equate them. Similarly take the y-components of two momentums before collision and after collision and equate If needed use the conservation of energy.Solve the equations to get the velocity of the second body.
  4. Dec 6, 2007 #3
    Yeah, i don't know why i labeled them incorrectly....sorry about that

    and thank you very much, i think i understand now
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