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: Horizontal Pulley System

  1. Nov 1, 2016 #1
    1. The problem statement, all variables and given/known data
    A group of construction workers are building a house and want to lower down an excess bundle of 1400 kg bricks to ground. They tie one end of a rope to the bundle of bricks, loop it through a pulley, and tie the other end of the rope to a toolbox. If the coefficient of kinetic friction between the toolbox and the floor is 0.690 and the acceleration of the bundle of bricks is 4.56 m/s2, what is the mass of the toolbox?
    where A=toolbox
    and B=bricks

    2. Relevant equations
    3. The attempt at a solution
    mA = ((gukmB)-(amB))/(a+g)
    I tried to solve by using this rearranged formula but did not get the right answer. I'm not quite sure what I'm doing wrong or what I'm missing. I am also assuming that acceleration (4.56 m/s2) is uniform, is this a correct assumption.
  2. jcsd
  3. Nov 1, 2016 #2

    Doc Al

    User Avatar

    Staff: Mentor

    I think you have your A and B reversed. Also, check your signs. (Let "a" be the magnitude of the acceleration.)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted