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!

Homework Help: TTU Dynamics: Find normal/angular acceleration of a point on a merry go round

  1. Nov 4, 2012 #1
    1. The problem statement, all variables and given/known data

    A boy mass mb and a girl mg are riding on a frictionless merry go round mr that has mass moment of inertia I = 1/2(mr)R^2. The boy runs back and forth from center to edge and completes a circuit in 2 seconds. If the initial speed is ωo, what is the acceleration the girl experiences on the outer edge R?

    2. Relevant equations

    I = 1/2(m)r^2
    F = ma
    M = dH/dt
    M = F cross r

    3. The attempt at a solution

    I have as my diagram a circle that I assume spins clockwise. The plane of the circle is the y-z plane, so I have all weights pointing in the -i direction. There is 1 degree of freedom. I can apply F = ma right away and get:

    F = -(mr + mb + mg)gi

    I am unsure of how to go about tackling the rest of the problem. I have to assume the merry go round is a circular plate. I assume the girl and boy can be treated as point masses, since no mass moment of inertia is given for them. My knowledge of angular dynamics is rusty. What am I not seeing here?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted