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Slide and Collide.

  1. Nov 24, 2007 #1
    [SOLVED] Slide and Collide.

    I need help getting started on this.

    A block of mass 12 kg lies at a vertical height 7.3 m on a frictionless incline plane. It slides down the plane and collides elastically with a second block whose mass is 6.8 kg. Find the final velocities of the two blocks.

    so far I got:
    (1/2)M1V1^2 = (1/2)M1V2 ^2 + (1/2)M

    V2 = ((M1V1^2) - (M1V1^2))/M2.

    I am not sure where to start.
     
  2. jcsd
  3. Nov 24, 2007 #2
    [tex]\frac{1}{2}M_1v_0^2=\frac{1}{2}M_1v_1^2+\frac{1}{2}M_2v_2^2[/tex]

    And also use conservation of momentum

    [tex]M_1v_0=M_1v_1+M_2v_2[/tex]
     
  4. Nov 24, 2007 #3
    Thanks.
    So the initial velocity of M1 at the top is zero right?
    Do I need to get the the velocity while the mass is sliding down the incline?
    If so, I will need to calculate the x direction, and then use the same velocity sliding down the incline as the initial velocity until it collides right?
     
  5. Nov 24, 2007 #4
    In this question nothing extra is given,so we can use just

    [tex]v_0=\sqrt{2gh}[/tex]
     
  6. Nov 24, 2007 #5
    Thanks, for the final equation, I got:

    Vbf - Vaf = -(Vbi - Vai)

    Is that right?
     
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