Torque and angular acceleration of two discs

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The discussion focuses on calculating the angular acceleration of two fixed disks using the equation Ʃτ = Iα. It confirms that since the disks are fixed together, they share the same angular acceleration. The participant struggles with determining the correct tension in the ropes, questioning whether it should be t = mg + ma due to acceleration. Clarification is provided to rely on the free-body diagram for accurate tension values rather than making assumptions. The overall approach emphasizes the importance of understanding the system's dynamics to solve for angular acceleration and tension effectively.
freshcoast
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Homework Statement



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Homework Equations



Ʃ\tau = I\alpha
ƩF = ma

The Attempt at a Solution



I was able to calculate A and B which I am confident is correct..

2r5dd1x.jpg


for part C is what I'm having trouble with. Since both disks are fixed together, does that mean they share the same angular acceleration? if so I think the way to go about this is I apply the equation

Ʃ\tau = I\alpha

where it will be T1R1 - T2R2 = I\alpha and I just solve for alpha.

but since they are now accelerating.. doesn't that change each tension to be t = mg + ma? instead of just t = mg ? which then makes it much more difficult to solve..

unless if the tensions are just mg then it will be fairly easy to solve since I can find the alpha of the rotating system then just apply the equation

a = \alphaR

and calculate the a for each, and from there I will be able to find the tensions in each rope.
 
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Since both disks are fixed together, does that mean they share the same angular acceleration?
Yes - that is what "fixed together" means. You needed to assume this to do (a) and (b).

since they are now accelerating.. doesn't that change each tension to be t = mg + ma?
Use the free-body diagram to inform you of the tensions. Don't anticipate.
 
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