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!

Forces and Motions Question

  1. Aug 12, 2013 #1
    1. The problem statement, all variables and given/known data
    In a tractor-pull competition, a tractor
    applies a force of 1.3 kN to the sled, which
    has mass 1.1 × 104 kg. At that point, the coefficient
    of kinetic friction between the sled
    and the ground has increased to 0.80. What
    is the acceleration of the sled? Explain the
    significance of the sign of the acceleration.

    m = 1.1 x 10^4 kg
    m =0.80
    2. Relevant equations



    Fnet= Fx+Fy

    3. The attempt at a solution

    ff=0.80 x (9.8)(1.1x10^4)
    ff= 86240

    86240=(1.1 x 10^4kg) a

    a= 7.85m/s2
  2. jcsd
  3. Aug 12, 2013 #2
    There are two forces acting on the sled here. One is by the tractor, the other is due to friction. By Newton's second law of motion, the NET force is equal to the product of mass and acceleration.
    Fnet = ma.

    You've considered only ff in calculating the acceleration.

    Also, make sure if you've taken the weight correctly. An 11 ton sled seems like a lot! :eek:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted