How to figure out this physics torque problem?

A torque of 12 Nm is applied to a solid, uniform disk of radius 0.50 m. If the disk accelerates at 4.5 rad/s^2, what is the mass of the disk?


________kgHow to figure out this physics torque problem?
Torque = moment of inertia x angular acceleration





Moment of inertia = 1/2mr*2





T = 1/2mr*2a





12 = 1/2m(0.5)*2(4.5)





m = 12(2)/0.5*2(4.5) = 21.3 kg





Hope that helps...How to figure out this physics torque problem?
Torque = (Inertia)(Angular Acceleration)


Inertia(of disk) = (1/2)(M)(R^2)


So


Torque/Angular Acceleration = (1/2)(M)(R^2)





Mass=[2(Torque/Angular Acceleration)]/(R^2)





Sorry I have no calculator right now, but the rest is just direct substitution, hope that helped!!

freckles