Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Glancing Collisions In 2D, help simplifying

  1. Nov 28, 2011 #1
    1. The problem statement, all variables and given/known data
    We are only given variables in this problem, that is:
    m1 travels at V, collides with 2m which is at rest
    results in m going off at 45° at V1
    2m also goes off at 45° down at V2
    Calculate V1 and V2 in terms of V


    2. Relevant equations
    Ʃρx-initial=Ʃρx-final
    Ʃρy-initial=Ʃρy-final
    Use Linear combinations; sin45= √2/2=cos45
    3. The attempt at a solution
    x direction:
    mv1=mv1√2/2+2mv√2/2
    y direction
    0=√2/2(mv1+2mv)
     
  2. jcsd
  3. Nov 28, 2011 #2

    PeterO

    User Avatar
    Homework Helper

    The equations you have written out are not quite right.

    You have:

    x direction:
    mv1=mv1√2/2+2mv√2/2
    y direction
    0=√2/2(mv1+2mv)

    but were perhaps trying for

    x direction:
    m1V=m1V1√2/2+m2V2√2/2
    y direction
    0=√2/2(m1V1+m2V2)

    Though perhaps you really did mean masses m and 2m ?
     
  4. Nov 28, 2011 #3
    yes the second mass was 2m as in twice the mass,
    i simplified the problem further and got a 90% on the paper so its fine :)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook