Results 1 to 2 of 2

Math Help - Conservation of Momentum

  1. #1
    Member WhoCares357's Avatar
    Joined
    Feb 2009
    From
    SC
    Posts
    88

    Conservation of Momentum

    A railroad flatcar of weight 7840 N can roll without friction along a straight horizontal track. Initially, a man of weight 596 N is standing on the car, which is moving to the right with speed 25 m/s; see the figure. What is the change in velocity of the car if the man runs to the left so that his speed relative to the car is 8.0 m/s?
    I set up the equation.
    [math ]m_1*v_1_i+m_2*v_2_i=m_1*v_1_f+m_2*v_2_f[/tex]
    [math ]0+0=\frac{596}{9.8}*8+\frac{7840}{9.8}*v_2_f[/tex]

    I came out with the answer -.076 m/s. Can anyone confirm this?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,698
    Thanks
    454
    Quote Originally Posted by WhoCares357 View Post
    I set up the equation.
    [math ]m_1*v_1_i+m_2*v_2_i=m_1*v_1_f+m_2*v_2_f[/tex]
    [math ]0+0=\frac{596}{9.8}*8+\frac{7840}{9.8}*v_2_f[/tex]

    I came out with the answer -.076 m/s. Can anyone confirm this?
    (M+m)v_0 = Mv_{1f} + mv_{2f}

    \frac{(M+m)v_0 - mv_{2f}}{M} = v_{1f}

    \frac{843.6(25) - 59.6(17)}{784} = 25.61 m/s

    \Delta v = v_{1f} - v_0 = 25.61 - 25 = 0.61 m/s
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. conservation of linear momentum
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: June 29th 2009, 05:03 AM
  2. Physics Problems: Conservation of Momentum
    Posted in the Math Topics Forum
    Replies: 5
    Last Post: February 21st 2009, 08:28 PM
  3. impulse and conservation of momentum
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: October 30th 2008, 12:29 PM
  4. conservation of energy
    Posted in the Math Topics Forum
    Replies: 4
    Last Post: October 28th 2008, 05:38 PM
  5. [SOLVED] Conservation of linear momentum
    Posted in the Advanced Applied Math Forum
    Replies: 6
    Last Post: July 3rd 2008, 10:22 PM

Search Tags


/mathhelpforum @mathhelpforum