A light string is wrapped around a spool (shape is unknown, thus you do not know moment of inertia I) of radius 0.5 m. A 5.0-kg mass is hung from the string, causing the spool to rotate and the string to unwind. The spool rotates from rest to 10 rad/s in 2 s. Find (a) the angular acceleration of spool, (b) moment of inertia I, and (c) the tension on the string.