Posted by **Lauren** on Sunday, July 29, 2012 at 6:28pm.

A spinning disk of mass 5.0 kg and radius 0.25m is rotating about an axis through its center at 400 rev/min.

a.) What is the angular velocity of the disk in rad/s?

b.) What is the moment of inertia of the disk?

c.) If it accelerates at a constant rate to 800 rev/min in 8 sec, what is its angular acceleration?

d.) What constant torque is required to produce this acceleration?

e.) When it reaches that speed, what is its kinetic energy?

f.) When it reaches that speed, what is its angular momentum?

- Physics -
**drwls**, Sunday, July 29, 2012 at 6:40pm
a) Convert revolutions per minute to radians per second. Surely you can do that.

b) The moment of inertia of a disc of radius R and mass M is

I = (1/2)M*R^2

c) Convert 800 rev/min to

w = ___ radians/sec, and divide that by 8.0 seconds for the angular acceleration, ____rad/s^2.

d) Torque = (Moment of inertia)*(angular accleration)

e) (1/2) I w^2

f) I*w

You do the numbers.

## Answer this Question

## Related Questions

- physics - A spinning disk of mass 5.0 kg and radius 0.25m is rotating about an ...
- Physics - A large disk of mass M and radius R is spinning like a CD of merry-go-...
- physics - A 1.6 kg disk with radius 0.63 m is rotating freely at 55 rad/s ...
- Physics - The moment of inertia of an object depends on the shape of the object...
- Physics - A woman with a mass of 50kg is standing on the rim of a large disk ...
- physics - Two disks are mounted (like a merry-go-round) on low-friction bearings...
- Physics - Two disks are mounted (like a merry-go-round) on low-friction bearings...
- physics - A solid disk rotates in the horizontal plane at an angular velocity of...
- Physics - A solid disk rotates in the horizontal plane at an angular velocity of...
- Physics - A solid disk rotates in the horizontal plane at an angular velocity of...

More Related Questions