physics
posted by George .
A solid disk pulley of mass 2.00 kg and a radius of 30.0 cm is rotated by a block mass of 0.500 kg falling from rest, a distance of 4.00 m. What is the mass's acceleration and how much time elapses during its fall?

F=ma is needed in rotational form
F*radius= I *angluar acceleration
Now F=mgma where a is acceleration.
(mgma)radius= I * a/r (angular acceleration is a/r)
look up I for a solid disk, solve for a.
Now, how much time:
distance=1/2 a t^2 solve for t. 
I had completed the problem correctly until when finding I for a solid disk I used 1/4 instead of 1/2. Thank you