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: Simple question

  1. Feb 18, 2008 #1
    A block of mass m is at rest on an inclined plane that makes an angle of 30º with the
    horizontal, as shown in the figure. Which of the following statements about the force of
    static friction is true?
    A) fs > mg D)fs = mg sin 30º
    B) fs > mg cos 30º E) None of these statements is true.
    C) fs = mg cos 30º

    because the only two forces acting on the block is fs and weight, F=0 since at rest, thus 0=fs - mgsin30 so
    fs= mgsin30

    So the answer is D right??
  2. jcsd
  3. Feb 18, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Yes. Very good.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook