1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Fridge about to tip, statics

  1. Feb 29, 2016 #1
    1. The problem statement, all variables and given/known data
    say a fridge of width "w" and height "L" is being pushed on by a force F at an angle θ to the horizontal. This force is applied at a height of "h" above the ground.

    I want to know what the max value of h can be such that the fridge doesn't tip and the coefficient of static friction is μ.

    2. Relevant equations
    ΣF = 0
    Στ = 0

    3. The attempt at a solution
    The force can be found:

    ΣFx = 0
    Fcosθ - f = 0, where f(max) = μN


    ΣFy = 0
    N - mg - Fsinθ = 0


    Fcosθ - μ(mg + Fsinθ) = 0
    F = μmg/(cosθ - μsinθ)

    This is my reasoning for the height, since only the horizontal component of F affects the perpendicular distance "h" to F, then:

    Στ = 0 (about axis where the fridge is about to tip)
    hFcosθ - mg(w/2) = 0
    h = ½mgw/(Fcosθ)

    Does that make sense? I'm skeptical about this.
  2. jcsd
  3. Feb 29, 2016 #2
    How you are pushing? F acting below the horizontal at theta angle or above the horizontal?
  4. Feb 29, 2016 #3
    Oups forgot to mention, the force is pushing above the horizontal, the vertical force is downward though
  5. Feb 29, 2016 #4
    If you are pushing in a direction above the horizontal then sin component will point up -in the direction of N

    so the sign of of F sin(theta) should change, if i am correctly following you!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted