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!

Physics:Incline planes

  1. Apr 5, 2007 #1
    A weightless pulley is attached to the top of an inclined plane which makes an angle of 30degree with the horizontal.Masses A and B,each of mass 1kg,are joined by an inextensible string passing over the pulley.Neglecting frictional forces,calculate the accleration of the masses and the tension in the string.(Shows working thanks)

    My working:
    let m2 be mass of b,m1 be mass of a.Assuming acceleration due to gravity to be 10m/s².
    m2g - T = m2a ---(1)
    T - sin30m1g = m1a ---(2)
    Substituting the values from the question,i have
    From (1): 10-T=a ---(3)
    From (2): T-5=a ---(4)
    Substitute (3) into (4):
    Substituting T into (3),

    Further Details
    The answers given to me was 2.5m/s² for acceleration and 75N for tension.
    Is the answers correct?
    If yes,any clues to get 75N?
    Thanks for replying.Appreciates it.
    Last edited: Apr 6, 2007
  2. jcsd
  3. Apr 5, 2007 #2


    User Avatar
    Homework Helper

    method looks good to me. is there a problem?
  4. Apr 6, 2007 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I would agree with mjsd, your method looks correct. I would suggest that the given answer is a typo and should read 7.5N as you have.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Physics:Incline planes