# What torque would have to be applied to a rod with a length of #1 m# and a mass of #2 kg# to change its horizontal spin by a frequency of #6 Hz# over #4 s#?

##### 1 Answer

The angular acceleration is

#### Explanation:

First find the angular acceleration,

The angular velocity is 6 Hz, and 1 Hz means that a circle of 2

Torque = moment of inertia *

moment of inertia depends on the shape of the spinning object and can be complicated. Fortunately for a mass on a rod it's simple:

moment of inertia = mass *

so:

moment of inertia = 2kg *

Now we have:

Torque = (2 kg

Torque = 6

or approximately :

Torque