For problem #38, I got 19.5 revolutions not 195.  Please explain how to go from -0.27 rad/s^2 for angular acceleration to revs.

Deborah, your answer is correct. The problem set is fixed. Thanks very much for your work.  John

For problem #67 I got 2.6 m/s

Matthias, you are correct, I posted the correction. Thanks for the help!  John

TY, I remember doing that and I just could not remember.  Thanks so much :)

Problem 85 C , I got 1.84/R, can you please explain how to get 1.44/R

Amany, we can't use a = r x alpha since the cylinder is slipping, so use torque = I alpha. The trick is finding the normal force. T + N = Mg, so N = 0.2 Mg. The Tension is acting in the up direction, causing the clockwise rotation. The friction force acts to the right opposing the rotation caused by the tension. Final equation is TR - friction x R = 1/2 MR^2. This will yield 1.44g/R as the solution.  John

Thank you