A spool of thin wire (with inner radius r = 0.50 m, outer radius R = 0.65 m, and moment of inertia Icm = 1.06 kg*m2 pivots on a shaft. The wire is pulled down by a mass M = 1.35 kg. After falling a distance D = 0.54 m, starting from rest, the mass has a speed of v = 70.200 cm/s. Calculate the energy lost to friction during that time. Not sure where even to begin!!