# What torque would have to be applied to a rod with a length of #5 m# and a mass of #2 kg# to change its horizontal spin by a frequency of #9 Hz# over #3 s#?

##### 1 Answer

Jan 27, 2018

Torque (

Now,moment of inertia of a rod w.r.t its one end along an axis perpendicular to its plane is

Now, as the radius of the circle isn't mentioned,so the rod can move about its mid point as well,in that case

Now, rate of change in angular velocity =

So,