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Homework Help: Physics 11

  1. Oct 19, 2004 #1
    Hi I'm new here, I hope someone can help me. I think I got the first half of the question, but I got stuck one the second part. Well here it goes,

    A force of 40N accelerates a 5.0kg block at 6.0m^2 along a horizontal surface.
    a.) How large is the friction force?
    b.) What is the coefficient of friction?

    a.) Fnet= ma
    Fp-Ff= ma
    (40)-Ff= (5)(6)
    40-Ff= 30
    40-30= Ff
    Ff= 10N

    I know that you have to use Ff= (mu)Fn, but how do you get Fn?

    And is there a way to show symbols like mu?
     
  2. jcsd
  3. Oct 19, 2004 #2
    Since the block moves in the horizontal direction only, the sum of the vertical forces equals zero. that is how you get fn.
    type to get the symbol.
    [tex]\mu[/tex]
     
  4. Oct 20, 2004 #3
    [tex]fn=mg=9.8*5*\mu[/tex]
    [tex]10=49\mu[/tex]
    [tex]\mu=.2[/tex]

    does this seem right? its been awhile
     
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