# What torque would have to be applied to a rod with a length of #5 # and a mass of #5 kg# to change its horizontal spin by a frequency of #3 Hz# over #4 s#?

##### 1 Answer

Dec 25, 2016

The torque is

#### Explanation:

The torque is the rate of change of angular momentum

The moment of inertia (spinning around the middle of the rod) is

The rate of change of angular velocity is

So the torque is