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 force

  1. Apr 30, 2010 #1
    Hi guys,

    I got this thought in my head.

    If I have a box of mass x, being pulled towards East and the angle [tex]\theta[/tex],
    then force applied to the box in order to move it on the surface with friction coefficient [tex]\mu[/tex] has to be in such a way:

    attachment.php?attachmentid=25494&stc=1&d=1272632393.jpg

    My question is... wouldn't N be:

    attachment.php?attachmentid=25496&stc=1&d=1272632659.jpg

    Or, N would be as usual W but in opposite direction? The drawing shows all the forces on the box:

    Cheers and thanks for the thought

    attachment.php?attachmentid=25495&stc=1&d=1272632393.jpg
     

    Attached Files:

    • 1.jpg
      1.jpg
      File size:
      3.8 KB
      Views:
      142
    • 2.jpg
      2.jpg
      File size:
      20.7 KB
      Views:
      146
    • 3.jpg
      3.jpg
      File size:
      3.8 KB
      Views:
      184
  2. jcsd
  3. Apr 30, 2010 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You got it.

    Nope. You were right the first time. The key is that there must be no net force on the box in the vertical direction.
     
  4. Apr 30, 2010 #3
    Ok thanks a mil! I was bit confused
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook