How Does Frictional Torque Affect Disk Rotation in Physics Experiments?

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Frictional torque opposes the motion of the disk, which is minimized by using a cushion of air. When the mass falls and the disk speeds up, the frictional torque acts in the opposite direction to the torque from the string. Conversely, when the mass rises and the disk slows down, the frictional torque again opposes the torque from the string. The magnitude of the disk's angular acceleration is greatest when the disk is slowing down, as both frictional torque and gravity contribute to the acceleration in that scenario. The logic presented in the discussion aligns with the principles of torque and angular acceleration in physics.
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The tension is not the only force producing a torque. There is also a frictional torque present that opposes the disk's motion (this is minimized by supporting the disk on a cushion of air). Use the "Top View" of the experiment in the simulation to answer the following questions.

When the mass is falling, and the disk is speeding up, how does the direction of the frictional torque compare to the direction of the torque from the string?

Same Direction or Opposite Direction

When the mass is rising, and the disk is slowing down, how does the direction of the frictional torque compare to the direction of the torque from the string?

Same Direction or Opposite Direction

When is the magnitude of the disk's angular acceleration largest? When the disk is speeding up or when it's slowing down?

Speeding up or Slowing down or Equal in both cases



My guess is the following...

1) and 2) Frictional Torque is the opposite direction because friction is always in the opposite direction of the force applied from gravity in this case.

3) My guess is that the acceleration is greatest when disk is slowing down because the acceleration is coming from both the frictional torque and gravity, compared to when its speeding up, where the acceleration of gravity is positive and greater than the negative acceleration coming from the frictional torque.


Can anyone please tell me if I'm right, and if my logic makes sense at all. Thanks.

Kevin
 

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