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!

Homework Help: Conservation of linear momentum!

  1. Jan 9, 2010 #1
    1. The problem statement, all variables and given/known data

    Two cars 1 and 2 moving against each other collides.There are no external forces acting on them.

    2. Relevant equations

    conservation of linear momentum:
    m1*v1+m2*v2 =(m1+m2)v12

    3. The attempt at a solution
    I have solved the problem but my question is how come they have a common speed after the collision?I dont understand this part can someone clarify it please.
  2. jcsd
  3. Jan 9, 2010 #2
    The equation you wrote is the one used when the two objects stick together when they collide, so after the collision there is only one object with a mass of m1+m2. This is called a perfectly inelastic collision. You can't use that equation if the objects bounce off each other.
  4. Jan 9, 2010 #3
    thanks a bunch mikelepore!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook