Question

In: Physics

A uniform disk of mass 371 kg and radius 0.19 m is mounted on frictionless bearings...

A uniform disk of mass 371 kg and radius 0.19 m is mounted on frictionless bearings so it can rotate freely around a vertical axis through its center (see the following figure). A cord is wrapped around the rim of the disk and pulled with a force of 10 N. What is the angular velocity (in rad/s) at the instant the disk has completed four revolutions. The disk starts from rest.

Group of answer choices

3.78 rad/s

3.87 rad/s

2.35 rad/s

2.53 rad/s

Expert Solution

Answer :Angular velocity ,

Explanation:

Distance covered in 4 revolutions,

Work done by the force (F=10N) to make 4 revolutions,

When an object is rotating about its center of mass, its rotational kinetic energy ,

where I is the moment of Inertia, for the disk and is the angular velocity

i.e

Work done by the force (F=10N) to make 4 revolutions will be equal to the rotational kinetic energy .

i.e

Substituting the values and ,

genius_generous answered 2 years ago

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