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!

Homework Help: 2 blocks, a light string and kinetic friction

  1. Oct 16, 2005 #1
    So, there are two boxes of fruit on a frictionless horizontal surface and are connected by a light string. m1=10kg, m2=20kg. A force of 50N is applied to the 20-kg box.
    There are two questions to answer, I already answered a:
    Determine the acceleration of each box, and the tension in the string:
    a= F/m1+m2 = 50N/30kg = 1.7 m/s^2 and T=m1a ... T=10kg(1.7 m/s) = 17 N.
    This is the one I can't figure out, b:
    Repeat the problem for the case where the coefficient of kinetic friction between each box and the surface is 0.10. So, mu k = .10
    I figured that the equation to use is Newtons 2nd Law, sum Fx=T-fk=m1a1. But I can't get it to work. I actually know the answer, but I don't know how to get there. Any help?:confused:
  2. jcsd
  3. Oct 16, 2005 #2
    Remember that the force of friction is always hold your force. So the sum of the forces will be:

    Fp - Ffriction = ma

    Find the friction and plug the number in.

    Then you can find our answer
  4. Oct 19, 2005 #3
    Thank You

    got it. I appreciate your help.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook