1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Collision of two particles

  1. Mar 12, 2016 #1
    1. The problem statement, all variables and given/known data
    A particle of mass 5.0kg travels initially with a velocity of 8.0mˆı and then interacts with a particle of mass 6.0kg which was initially at rest. After the interaction the 5.0kg mass travels at a speed of 4.0m/s along a direction which makes an angle of 53◦ with the x-axis.

    What is the change in momentum of the 5kg mass? -28i -16j
    What is the speed of the 6kg mass after the interaction?


    2. Relevant equations
    m1v1=(m1v2)f+m2v2

    3. The attempt at a solution
    So I am thinking the momentum must be conserved. If the initial velocity was 8m/s in the i direction, the final velocity must be as well. The final velocity of the 5kg mass in component form is 4cos(307)=2.4i and 4sin(307)=-3.2j. This means the final velocity of the 6kg mass is 5.6i and 3.2j, giving 6.5 as the final velocity.

    Apparently the answer is 5.4, can you show me what i should be doing instead. Thanks :)
     
  2. jcsd
  3. Mar 12, 2016 #2
    These two statements, don't mean the same thing. How did you conclude that the final velocity must equal the initial?
     
  4. Mar 13, 2016 #3
    Ok i see what i did wrong, lol, long day.
    Total initial momentum: 40i
    5kg mass final momentum: 12i, -16j
    Due to conservation of momentum: 6kg final momentum: 28i, 16j
    sqrt((28/6)^2+(-16/6)^2)
    final speed: 5.4m/s
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted