Hi, So I have a DC motor powering a whisk (http://upload.wikimedia.org/wikipedia/commons/8/85/Schneebesen1.JPG). Imagine the whisk on the end of the motor shaft. I'd like to know what torque requirements I have for the motor to ensure that it can successfully spin the whisk. Background To accelerate the whisk to a speed w the motor must generate a torque T such that: Tm = Jl x dw/dy where: Tm = torque generated by the motor Jl = inertia of the whisk dw/dy = angular acceleration of the whisk The Problem In order to solve this equation I need to determine the inertia of the whisk, Jl, such that: Jl = m x R where: m = mass of whisk (80gms) R = distance of whisk from point of rotation (0cms?) So my question is basically how to calculate the moment of inertia for a whisk? The confusion arises as it appears the centre of mass of the whisk lies on the axis of rotation, there is therefore no moment of inertia. As there is no moment of inertia, the motor generates no torque (or an infinite torque). So, should I apply the above formula assuming that the centre of mass of the whisk is focused at the outer edge of the whisk...or is there a more logical approach.