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4t0mic
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Homework Statement
A 103 g Frisbee is 16 cm in diameter and has about half its mass spread uniformly in a disk and the other half concentrated in the rim. With a quarter-turn flick of the wrist, a student sets the Frisbee rotating at 730 rpm.
a) What is the rotational inertia of the Frisbee?
b) What is the magnitude of the torque, assumed constant, that the student applies?
Homework Equations
[tex]I = \frac{1}{2}MR^{2}[/tex]
[tex]I = MR^{2}[/tex]
[tex]\tau = I\alpha[/tex]
The Attempt at a Solution
I already solved for the rotational inertia from the combination of [tex]I =\frac{1}{2}MR^{2}[/tex] and [tex]I = MR^{2}[/tex]. But I can't seem to get how to get the torque from [tex]\tau= I\alpha[/tex]. I know what I (rotational inertia) but I don't know how to get [tex]\alpha[/tex]. Help me figure it out! Thanks.