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 velocity changes from 1 Hz to 4 Hz in 1 s, what torque was applied to the object?

1 Answer
Dec 25, 2016

The torque is =75.4Nm

Explanation:

The torque is the rate of change of angular momentum

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

The is I=1/2mr^2

=1/2*2*2^2= 4 kgm^2

The rate of change of angular velocity is

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

=6pi rads^(-2)

So the torque is tau=4*6pi Nm=24piNm=75.4Nm