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!

What is the acceleration of the cart? :)

  1. Apr 20, 2017 #1
    1. The problem statement, all variables and given/known data
    A man is pulling himself up the 15 degree incline by the method shown. If the combined mass of the man and the cart is 100kg, determine the acceleration of the cart if the man excerpts 250 N on the rope. There is also a .2 coefficient for the kinetic friction between the wheels and the ground.

    2. Relevant equations

    F=m*a
    Fk=μ*N
    3. The attempt at a solution
    So I pretty much know how to solve this without friction being involved. Where T is the friction in the rope, m is the mass of the man and cart theta is the angle, and a is acceleration.

    F=m*a
    4T-m*g*sinθ=m*a

    now when you throw friction into the mix should it look like this?
    F=m*a
    4T-m*g*sinθ-μ*N=m*a
    4T-m*g*sinθ-μ*m*g*cosθ=m*a

    with the numerical values
    4*(250)-100*9.81*sin(15)-.2*100*9.81*cos(15)=100*a
    a=5.566m/2^2


    Thanks ahead of time, you all rock
     
  2. jcsd
  3. Apr 20, 2017 #2
    Is there a figure you can attach?
     
  4. Apr 20, 2017 #3

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Sack the question setter. Presumably the wheels are rolling, so kinetic friction between them and the ground is irrelevant, and static friction would not cost any energy. It should say "rolling resistance", not friction. (0.2 is rather high.)
    You mean tension, I assume.
    I infer that the pulley system involves four lengths of rope between the cart and the top of the slope. If so, your method and answer look fine.
     
  5. Apr 20, 2017 #4
  6. Apr 20, 2017 #5
    yea, tension in the rope not friction
     
  7. Apr 20, 2017 #6
    and are you saying the question is worded incorrectly? because that was a word for word question by professor wrote
     
  8. Apr 20, 2017 #7

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

  9. Apr 20, 2017 #8
    okay well thanks for pointing that out. we have a forum for our class, so I'll let others know.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: What is the acceleration of the cart? :)
Loading...