This isn't really a homework problem, more of a "I'm-building-something-and-need-to-make-sure-the-physics-are-right-before-I-build-something-impractical" problem. 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution (I grouped it all together, easier for me to not separate each segment) I need to spin a motor handle/crank at 25,000 rpm. I need to show that using a single flywheel attached to the spinning motor handle is unpractical. I know that 25,000rpm is ~2618 rad/sec; this value should be angular frequency, ω, correct? Then relating that to torque, tau = Iω, where I = mr^2 for a ring of radius r and mass m. And torque also equals tau = rFsinθ, where θ = 90°. Therefore, Iω = rF and F = mrω. Assuming m = 1 kg, r = 0.5 m, F = ~1309 N Therefore torque = ~655 Nm. Are the physics relationships correct? Thanks in advance. EDIT: Also, tangential velocity is v = rω, correct?