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!

Conservation of Momentum question

  1. Nov 3, 2015 #1
    1. The problem statement, all variables and given/known data


    Two carts sit on a horizontal, frictionless track; the spring between them is compressed. The small cart has mass m, and the mass of the larger cart is M = 4.65m.
    NOTE: Every velocity needs magnitude and direction (given by the sign).

    a) Suppose the carts are initially at rest, and after the "explosion" the smaller cart is moving at velocity v = +8.71 m/s.
    - Find the velocity of the larger cart. V = (answer) m/s
    - Assume now that the mass of the smaller cart is m = 6.36 kg. Assuming there is no loss of energy: find the energy stored in the spring before the explosion. Wk = (answer)J
    - If the spring has spring constant k = 276 N/m: find x, the distance the spring was compressed before the "explosion".




    2. Relevant equations
    F=kx
    PE(spring) = 1/2 kx^2
    MV+MV=MV+MV

    3. The attempt at a solution

    part a) I know that if both carts have the same mass then both will be moving away from each other at the same speed after the spring explodes, so it would be -8.71 . But one cart has higher mass, so one cart will move faster away. So I use the conservation of momentum formula
    MV+4.65M*O = M8.71+4.65M*V
    what do I do, solve for V? I cant, the algebra does not work out, am I missing a formula?
     
  2. jcsd
  3. Nov 3, 2015 #2

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Why do you have a V on the left?
    Note that every term has a factor m. What does that allow you to do?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Conservation of Momentum question
Loading...