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!

Equivalent angles and Trig Fucntions

  1. Sep 4, 2012 #1
    1. The problem statement, all variables and given/known data

    A block with mass M is held statically on an overhang by a force Mg applied horizontally and the force of friction on the overhang. What are the normal and frictional forces? For what angles θ does the block remain at rest?

    3. The attempt at a solution

    In the picture I've drawn out the forces acting on the block. I understand the ideas behind static equilibrium. What I have trouble with is understanding which trig fucntions to use when comparing the forces and how to identify which angles are equivalent to the angle θ in the problem. Can anyone explain the thought process behind determining these things?
     

    Attached Files:

  2. jcsd
  3. Sep 4, 2012 #2

    rock.freak667

    User Avatar
    Homework Helper

    To get the forces N and Ff, you will have to split the weight into two components, one perpendicular to the plane and one parallel to the plane. If we redraw the two forces like this: (reducing the block to a small point)

    iz702v.png


    The angle formed by the line mg and the horizontal is 90 degrees and the angle formed by the normal of the plane and the plane itself is?

    When you get that you can easily see where the angle a will be in relation to N and mg.

    Draw in the 90 degree angles one at a time for each triangle.
     
  4. Sep 4, 2012 #3
    The force that keep the block from falling is a component of frictional force.
    FfSinθ=mg
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Equivalent angles and Trig Fucntions
  1. Fucntional Analysis (Replies: 14)

Loading...