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!

Momentum of System

  1. Nov 9, 2008 #1
    1. The problem statement, all variables and given/known data
    A system initially consists of a ball of mass m at rest at a height h above the Earth and the Earth, of mass Me. When the ball has fallen a distance h/2, the total momentum of
    the system is
    A. 0
    B. m(sqrrt)2gh
    C. Me(sqrrt)2gh
    D. Me + m(sqrrt)2gh
    E. Me - m(sqrrt)2gh


    2. Relevant equations



    3. The attempt at a solution
    I put B and missed it. I think the answer is C but not sure.
    Any help understanding this would be appreciated.
    Thanks,
    Kevin
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Nov 9, 2008 #2

    [tex]\textbf{v}_f^2=\textbf{v}_i^2+2\textbf{ad}[/tex]

    so, [tex]\textbf{v}=\sqrt{2\textbf{ad}}[/tex], and:

    [tex]\textbf{p}=m\textbf{v}=m\sqrt{2\textbf{ad}}[/tex].

    The total momentum of the system is the sum of momenta of the particles. The above momentum is that of the ball. The momentum of the earth is given by:

    [tex]M_e\textbf{v_e}=[/tex],

    add them and that's your answer which isn't readily available, sadly. Maybe someone else has more of an intuitive approach.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Momentum of System
  1. Momentum of the system (Replies: 4)

Loading...