A light string is wrapped around a spool of radius 35 cm. Shape of spool is unknown, thus you do not know moment of inertia. A 15 kg mass is hanging from a string, causing the spool to rotate and the string to unwind downward. The spool rotates from rest to 25 rad/s in 12 s. Find
(a) the angular acceleration of the spool,
(b) the moment of inertial, and
(c) the tension on the string. I have a test on this and Im having trouble understanding it.