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**1. Homework Statement**

Massive spinning flywheels (disks) can be used for storing energy. Consider a flywheel with a diameter of 1.10 m and a mass of 510 kg. A constant force of magnitude F is applied tangentially to the rim of the flywheel to accelerate it from rest to 4.00 x 103 rev/min during 2.85 min.

(b) What magnitude of torque is necessary to cause this angular acceleration?

**2. Homework Equations**

I = mR[tex]^{2}[/tex]

[tex]\tau[/tex] = I[tex]\alpha[/tex]

**3. The Attempt at a Solution**

I = mR[tex]^{2}[/tex]

I = (510kg)[tex]\ast[/tex](.55m)[tex]^{2}[/tex]

I = 154.275 kgm[tex]^{2}[/tex]

[tex]\tau[/tex] = I[tex]\alpha[/tex]

[tex]\tau[/tex] = (154.275kgm[tex]^{2}[/tex])\ast(2.449rad/s[tex]^{2}[/tex]

[tex]\tau[/tex] = 377.819 Nm

The answer was incorrect. Also the angular acceleration was derived from part a and is the correct number. Thanks for the help.