# An object with a mass of  2 kg is traveling in a circular path of a radius of 4 m. If the object's angular velocity changes from  1 Hz to  3 Hz in  2 s, what torque was applied to the object?

Feb 13, 2016

$L = 64 \pi$

#### Explanation:

$\alpha = \frac{\Delta \omega}{\Delta t}$
$\text{alpha is the angular acceleration for object}$
$\alpha = \frac{2 \pi \cdot {f}_{f} - 2 \pi \cdot {f}_{i}}{2}$
$\alpha = \frac{2 \pi \cdot 3 - 2 \pi \cdot 1}{2}$
$\alpha = 4 \frac{\pi}{2}$
$\alpha = 2 \pi$
$\text{L:torque}$
$L = \alpha \cdot I$
"I=m*r^2
$L = 2 \pi \cdot 2 \cdot {4}^{2}$
$L = 64 \pi$