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Conservation of Momentum: Pulley System

  1. Nov 4, 2016 #1
    1. The problem statement, all variables and given/known data
    Block A (of mass MA) rests on a frictionless horizontal table. It is connected via a light string to block B (of mass MB) hanging over the edge of the table. The pulley itself, a solid disc, has non-negligible mass MC. The light string does not slip over the pulley.
    What is the magnitude of the linear acceleration of the system?

    Edit: Messed up with the title! This problem is in the chapter of Conservation of Momentum in my book but I actually didn't use it for this problem.
    2. Relevant equations
    Στ=Iα
    α=a/r
    Moment of Inertia of a disk = 1/2mr^2

    3. The attempt at a solution
    So here's my attempt but I'm not sure where I'm messing up.
    FullSizeRender 2.jpg
     
  2. jcsd
  3. Nov 4, 2016 #2
    Your work looks correct .

    Why do you think you are messing up somewhere ?
     
  4. Nov 4, 2016 #3
    When I enter my answer into my online hw answer checker, it says it's wrong. I'll have to ask my professor if maybe there's a mistake with his website cause sometimes he messes up!
    Thanks though!
     
  5. Nov 4, 2016 #4
    I don't know where you're messing up. I didn't see anything wrong.
     
  6. Nov 4, 2016 #5
    That is probably what happened. I went through the problem twice and got the same result both times.

    Acknowledging @Vibhor who answered before me. I didn't see it until after I posted.
     
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