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!

Energy and Friction in a block

  1. May 5, 2017 #1
    1. The problem statement, all variables and given/known data
    upload_2017-5-5_18-2-1.png

    2. Relevant equations
    The block has potential energy U at the top of the ramp, and this is transfered to kinetic energy K at the bottom, which is then trasnfered to work done by friction, Wfr.
    U = K Conservation of energy
    K = Wfr Conservation of energy
    g = 10 m/s2


    3. The attempt at a solution
    U = mgh = 3*45*10 = 1350 J
    1350 J = Wfr = Ffr * d = m*g*u*d = 3*10*1*d
    1350 = 30*d
    d = 45 m

    This does not match the answers. Am I doing anything wrong?
     
  2. jcsd
  3. May 5, 2017 #2

    gneill

    User Avatar

    Staff: Mentor

    Your calculations are correct. There is likely an error in the problem statement. I suspect that they intended the coefficient of kinetic friction to be 0.1. Your answer of 45 m is correct for the given information.
     
  4. May 5, 2017 #3
    That is a very good point. We usually don't see coefficients of friction to be 1.0, so it probably was 0.1. I just wanted to make sure my understanding of work-energy relationship was correct. Thanks!
     
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: Energy and Friction in a block
  1. Friction on a block (Replies: 10)

  2. Blocks and Friction (Replies: 3)

Loading...