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!

Friction problem again Okay today is not my day

  1. Sep 11, 2008 #1
    1. The problem statement, all variables and given/known data

    A passennger is standing without slipping in a forward accelerating train. The coeffeciant of the feet and the floor is 0.47. Determine the maximum required acceleration of the train relative to the track if the passenger is not to slip

    2. Relevant equations


    3. The attempt at a solution

    I know that acceleration = 0, but when I rearrange the equations. I end up with
    F(a) = ma + (mu)mg. But I only know (mu)... so I end up not being able to solve it.
  2. jcsd
  3. Sep 12, 2008 #2


    User Avatar
    Homework Helper

    If you consider things from the reference frame of the ground, the man is accelerating with the same acceleration as the train. Write out Newton's law in that case. What forces are acting on him? Once you use that in Newton's law, you should find that you only have one unknown left in your equation.
  4. Sep 13, 2008 #3
    but I'm not given the train's acceleration... am I missing something here =/?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Friction problem again Okay today is not my day
  1. Friction again (Replies: 3)