A disk with a red (inner) and green (outer) block attached to it is spinning at

Question

A disk with a red (inner) and green (outer) block attached to it is spinning at constant angular acceleration. The disk has a radius of 10.0 cm and a mass of 1.2 kg; the green block has mass of 0.5 kg and is 8.0 cm from the center of the disk; the red disk has a mass of 0.8 kg and is 4.0 cm from the center of the disk.

In the space below answer the following questions:

a) Is there a net force on the green block? Explain.

b) Is there a net torque on the red block? Explain.

c) Is there a net torque on the disk? Explain.

d) Calculate the moment of inertia of the system (disk and blocks). Show your work.

I need DETAILED explanations, best one gets the points.

Explanation / Answer

a) Yes, since the green block is also movibg in circular motion, there must be a centripetal force acting on it...

This centripetal force is the result of the FRICTION force present between the block and the disk, that keeps the block moving...

b) Yes there is a net torque acting on the block...Since it is moving with constant angular acceleration...Also, we know that toque = Moment of inertial (I) * alpha (angular accn)

Dont get confused here...with the disk, the blocks are also moving with a constant acceleration...and have a certain moment of inertia of their own...

This is can happen only if there is a net torque acting on it!!!

c) Yes, there is a net torque on the disk...Since it is moving with constant angular acceleration...Also, we know that toque = Moment of inertial (I) * alpha (angular accn)

d) The moment of inertia = NET TORQUE on the system / Net angular acceleration

Here the values are not given, so i can not give you the exact numerical answer...

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