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

1 Answer
Jan 3, 2017

The torque is =150.8Nm

Explanation:

The torque is the rate of change of angular momentum

tau=(dL)/dt=(d(Iomega))/dt=I(domega)/dt

The moment of inertia of the object is I=mr^2

=2*2^2= 8 kgm^2

The rate of change of angular velocity is

(domega)/dt=(4-1)/1*2pi

=(6pi) rads^(-2)

So the torque is tau=8*(6pi) Nm= 48piNm=150.8Nm