- #1
skysunsand
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Homework Statement
A cord 3.0 m long is coiled around the axle of a wheel. The cord is pulled with a constant force of 40N. When the cord leaves the axle, the wheel is rotating at 2.0 rev/s. Determine the moment of inertia of the wheel and axle. Neglect friction. (Hint: The easiest solution is by the energy method)
Homework Equations
KE= 1/2 mv^2 + 1/2 I w^2
I= Mr^2
The Attempt at a Solution
I'm completely lost. I don't have a mass to work with, so I can't use these equations. But then I have no clue what equation I WOULD use. I know the answer is 1.5kg*m^2, but I have no clue where that comes from.
Ideally, I think I'd like the radius of the wheel, but I'm not told how many times that cord is wrapped around the wheel, so I can't use the circumference to find the radius...