A solid, frictionless cylindrical pulley has a radius R = 0.550
m. A block is attached to a cord that is wrapped around the outside
of the pulley. The block is falling with a downward acceleration of
3.80 m/s2, and the tension in the cord is 0.850 N. The free body
diagrams for the pulley and the block are shown to the right. Note
that the magnitudes of the two tensions T1 and T2 are equal. (Just
call the tension T.) Also, "n" in the free body diagram of the
pulley represents the normal force provided by the axle of the
pulley, equal in magnitude to the weight of the pulley. Note that
the normal force and the weight force do not produce torques on the
pulley. (Why is this?)