A positive acceleration means that the red mass accelerates up, the blue mass accelerates down, and the pulley has a clockwise angular acceleration. All the directions are reversed when the acceleration is negative.
The pulley is assumed to be a solid disk rotating about its center, with a moment of inertia of 0.5 mr2.
Things to think about:
Created by Andrew Duffy, Boston University Physics Department.
Last update October 21, 1998