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!

Friction force problem

  1. Mar 31, 2015 #1
    A 1.2 kg block is resting on horizontal surface. The coefficient of static friction between block and
    surface is 0.5. What is the magnitude and direction of force of friction on block when magnitude of external force acting of block in the horizontal direction is 9.8 N



    fs = μs*N, N = mg
    upload_2015-3-31_18-52-3.png

    m = 1.2 kg, μs = 0.5, g = 9.8
    fs = 0.5*1.2*9.8 N = 5.88 N
     
  2. jcsd
  3. Mar 31, 2015 #2
    Is this really the full problem statement, exactly as presented, because something seems wrong about it.

    Chet
     
  4. Mar 31, 2015 #3
    please tell me what is wrong about it?
     
  5. Mar 31, 2015 #4
    If the applied force is less than the normal force times the coefficient of static friction, then the friction force will equal the applied force and the body will not move. If the applied force is equal to the normal force times the coefficient of static friction, then the friction force will equal the applied force and the body will be on the verge of moving. But, in your example, the applied force is greater than the normal force times the coefficient of static friction, so the body will move, and kinetic friction will prevail; in this case, the coefficient of static friction is irrelevant, as is the normal force times the coefficient of static friction.

    Chet
     
  6. Mar 31, 2015 #5
    S
    So can the force of kinetic friction be found? if so how to find
     
  7. Mar 31, 2015 #6
    To find that, you need to know the coefficient of kinetic friction.

    Chet
     
  8. Mar 31, 2015 #7
    Yes it was the same doubt i had. can the coefficient of kinetic friction be found
     
  9. Mar 31, 2015 #8
    Sure, it can be measured.

    Chet
     
  10. Mar 31, 2015 #9
    thanks
     
  11. Apr 2, 2015 #10
    Oposed to motion
     
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: Friction force problem
  1. Friction/Force Problem (Replies: 10)

Loading...