ok so calculators at the ready, to give a basic idea as to what KE you can produce with a spinning disc or bar, you need to do this: -

1/2 (half) Inertia X angular velocity2 (squared)

Angular velocity is = velocity divided by radius

Inertia = 1/2 MR2 (squared) M=Mass KG R= Radius Meter

so try and work that out, actually i dont think thats right ill have to check again