Why is my rotational mechanics homework solution not matching the given choices?

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The discussion centers on a student struggling to match their solution for a rotational mechanics homework problem with the provided answer choices. They applied the net torque and force equations but arrived at an acceleration value of 9.2, which is not among the options. Other participants suggest that the tension in the pulley may not be equal on both sides, prompting a reevaluation of the equations used. They recommend using three equations to solve the problem correctly. Clarifying the assumptions about tension is crucial for finding the correct answer.
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Homework Statement


screenshot_47.png


Homework Equations


Net Torque = Moment of Inertia * Angular Acceleration
Net Force = Mass * Acceleration

The Attempt at a Solution


I first applied the first formula on the pulley, I found out that Tension Force = Acceleration
Then, I used Newton's second law on m1 which gave me: 120 - T = 12a ---> 120 - a = 12a ---> 13a =120 ---> a = 9.2

Which is not on the choices,,
any help please
thank you
 
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Sarah00 said:
I first applied the first formula on the pulley, I found out that Tension Force = Acceleration
What did you do here ? How is force of tension equal to acceleration ?

Hint : Is tension on both sides of the pulley the same ? Why / Why not ?
Also , your solution will require three equations .

Hope this helps .
 
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