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!

Simple Forces question I cannot seem to get

  1. Jan 25, 2013 #1
    1. The problem statement, all variables and given/known data
    A couch weighing 620N is to be pushed to a new location across the room. The coefficent of static friction between the couch and the floor is 0.31. What is the minimum force required to set the couch into motion.

    2. Relevant equations
    See below


    3. The attempt at a solution
    Given: Fg=620N
    μs=0.31
    Required: Force applied
    Analysis: In order for the couch to begin moving, the applied force must be equal to the force of friction. Therefore finding the force of friction will indirectly find the minimum force applied.
    Solution: Find the mass of the couch by using Fg=mg=620N
    mg=620N
    m=620N/9.81m/s^2
    m=63.2...kg (keep all the decimals)

    then find Ff using Ff=μFn; since there is no vertical acceleration, Fg=mg. The question gave mg (620N) so...
    Ff=(0.31)(620N)
    Ff=192N [backwards]
    Fa=192N [forwards]

    Therefore 192N of force are required.

    Is this solution correct?
     
  2. jcsd
  3. Jan 25, 2013 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Looks ok to me. But you didn't need to to find m.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook