Question: A light string 4 m long is wrapped around a cylindrical spool with a radius of 0.075 m and a mass of .5 kg. A 5 kg mass is then attached to the free end of the string causing the string to unwind from the spool. a) What is the angular accelerataion of the spool? b) how fast will the spool be rotating after all of the string has unwound? I got an answer of 2613.333 for (a), but my teacher claims the answer is wrong. I just want to solve this problem or else it's going to kill me...so if any of you know how, please reply. He said the tension must be solved first. but i have no idea. i though the time would be .9 but seems not.