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 3 Hz to 8 Hz in 1 s, what torque was applied to the object?

1 Answer
Mar 28, 2018

The torque is =251.3Nm

Explanation:

The torque is the rate of change of angular momentum

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

where I is the moment of inertia

For the object, I=mr^2

The mass is m=2 kg

The radius of the path is r=2m

So the moment of inertia is

,I=2*(2)^2=8kgm^2

The angular acceleration is

alpha=(2pif_1-2pif_0)/t=(16-6)pi/1=10pirads^-2

So,

The torque is

tau=Ialpha=8*10pi=251.3m