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: Momentum in 2-D

  1. Oct 29, 2009 #1
    1. The problem statement, all variables and given/known data
    A 850 kg car is traveling west at 25.0 m/s when it collides with a 1050 kg car that was initially traveling north at 10.5 m/s. The cars lock together, and eventually skid to a stop.
    What is the velocity of the cars immediately after the collision?

    2. Relevant equations
    pi=pix i + piy j + piz k

    3. The attempt at a solution
    I got an answer but I'm not sure if it is correct. I just need someone to verify if what I did is correct.
    Here's what I did:
    I found pi using the equation above and then took the magnitude of that to find pf as shown below:

    (-(850 kg)(25.0 m/s) i)2 + ((1050 kg)(10.5 m/s) j)2=pf2

    I then took the pf value and set that equal to the total mass times the velocity:

    2.39 x 104 kg*m/s=(850 kg + 1050 kg)v

    I then solved for v to get the following:

    v=12.6 m/s
  2. jcsd
  3. Oct 29, 2009 #2


    User Avatar
    Homework Helper

    Your answer is correct.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook