I believe I solved it thanks to all of your help. The forces acting on the mass are gravity (mg) and the tension of the string (T). There is one torque acting on the spindle ( tf). The net torque on the mass is mg - T= ma which can be rewritten as T= mg - ma. The net torque on the spindle is tf...
Homework Statement
Find an expression for the moment of inertia (I) of the platform in terms of acceleration of the mass (a), the value of the hanging mass (m), the radius of the spindle (r) and the constant (g).
Diagram: http://i.imgur.com/rv3zFYG.jpg
Homework Equations
F=ma t=Iα...