# Magnitude of Torque

## 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?

## Homework Equations

I = mR$$^{2}$$
$$\tau$$ = I$$\alpha$$

## The Attempt at a Solution

I = mR$$^{2}$$
I = (510kg)$$\ast$$(.55m)$$^{2}$$
I = 154.275 kgm$$^{2}$$

$$\tau$$ = I$$\alpha$$
$$\tau$$ = (154.275kgm$$^{2}$$)\ast(2.449rad/s$$^{2}$$
$$\tau$$ = 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.