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: Finding angle of rope that gives max capable weight for loaded crate to be pulled

  1. Oct 26, 2012 #1
    1. The problem statement, all variables and given/known data

    An initially stationary box of sand is to be pulled across a floor by means of a cable in which the tension should not exceed 1220N. The coefficient of static friction between the box and the floor is 0.24. (a)What should be the angle between the cable and the horizontal in order to pull the greatest possible amount of sand, and (b) what is the weight of the sand and box in that situation?

    2. Relevant equations

    3. The attempt at a solution

    dm/dθ= (-F/a)cosθ.....
  2. jcsd
  3. Oct 26, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Before the object can accelerate, it first has to overcome static friction in the equilibrium condition(a =0). m is maximized when dm/dθ = ?. Try a free body diagram to identify forces acting, and use Newton 1 in the y direction , and Newton 1 in the x direction at the limiting value of the static friction force.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook