A mass of .375kg hangs from a string that is wrapped around the circumference of a pulley with the moment of inertia = .0125 kg*m^2 and a radius of .26m. When the mass is released, the mass accelerates downward and the pulley rotates about its axis as the string unwinds. What is the acceleration of the mass?? I have been using a=rF/mr^2, with my F=mg. The correct answer is 6.57m/s^2, but i can't seem to figure out why. No rush on answering, the question is from a practice exam I am studying. Thanks guys.