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!

Mass hanging in a boxcar accelerating

  1. Apr 8, 2016 #1
    1. The problem statement, all variables and given/known data
    A mass of 1 kg hangs inside a boxcar of a train. If the train accelerates at 7 m/s^2, what is the approximate tension in the rope?

    A: 12 N

    2. Relevant equations
    F=ma

    3. The attempt at a solution
    I originally thought of doing this problem as pythagorean theorem, but I wanted to work out the x and y components for practice. Breaking up the components:
    ΣFy=may
    Ty-mg = may
    Ty=10N

    ΣFx=max
    Tx=10*7
    Tx=70N

    Thus, T2=102+702
    T=71 N

    The problem sets it up just like I do but get 12 N for their answer:
    T2=ma2+mg2

    What am I doing wrong? Thanks in advance!
     
  2. jcsd
  3. Apr 8, 2016 #2

    berkeman

    User Avatar

    Staff: Mentor

    Can you show us your free body diagram for this problem? That is generally the first/best step on these problems. :smile:
     
  4. Apr 9, 2016 #3

    gneill

    User Avatar

    Staff: Mentor

    Check the mass value used for the calculation of the x-component.
     
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: Mass hanging in a boxcar accelerating
Loading...