1. Not finding help here? Sign up for a free 30min 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!

Three blocks colliding- velocity and angle of the third, so they come to rest

  1. Oct 30, 2009 #1
    1. The problem statement, all variables and given/known data

    Two blocks (m1 = 0.02 kg, m2 = 0.03 kg, v1 = 1.5 m/s, v2 = 0.5 m/s) are sliding without friction on a surface. They are approaching each other at angle θ = 60º. In what direction and with how much velocity do we have to push the third block (m3 = 0.05 kg) against the first two blocks, so that when they crash they will come to rest?

    2. Relevant equations

    p=mv

    3. The attempt at a solution

    First two blocks:

    G(x)= m(2)v(2)*(-sin θ)
    G(y)= m(1)v(1) + m(2)*cos θ

    Third block:

    G(3x)= sin θ

    G(3y)= m(1)v(1) – m(2)v(2)*cos θ

    For the direction of the third block:

    tan θ’= m(2)v(2)*sin θ / m(10v(1) + m(2)v(2)*cos θ → θ’= 19.1º

    For the velocity of the third block:

    G(3)= m(3)v(3) → v(3)= G3 / m(3)

    G3= sqrt(m(1)²v(1)² + m(2)²v(2)² +2m(1)v(1)m(2)v(2)*cos θ)= 0.039686

    v(3)= G3 / m(3)= 0.79372 m/s

    Are my calculations correct?
     
    Last edited: Oct 31, 2009
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted



Similar Discussions: Three blocks colliding- velocity and angle of the third, so they come to rest
  1. Block with friction (Replies: 0)

Loading...