How to Calculate Tension and Velocity in a Rotational System?

AI Thread Summary
To calculate the angular velocity and linear velocities in the given rotational system, the moment of inertia is crucial, but insufficient information is provided regarding the disks' dimensions. The problem suggests assuming that the mass M represents both disks, yet the thickness of each disk remains unknown, complicating the calculations. It is recommended to treat M as the total mass of a pulley composed of two disks of equal thickness and material. This approach simplifies the problem, allowing for a more straightforward calculation of tension in the strings. Ultimately, the lack of complete data makes the problem challenging to solve accurately.
Axel H
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Homework Statement



http://imageshack.us/photo/my-images/545/rotacion1.jpg/
Translation: Determinate, for the system of Fig. 10-39 the angular velocity of the disk and the linear velocity of m and m'. Calculate the tension in each string. Suposse that m = 600 g, m' = 500 g, M = 800 g, R = 8 cm and r = 6 cm.


Homework Equations





The Attempt at a Solution


The problem is I don't know to get the moment of inertia because I have the mass of one disk only.
 
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I agree, it looks like you were not given enough information.

One could assume that M was for both discs, but you would still need to know the thicknesses of the two discs which you could estimate if you had to.

Bad problem.
 
Solve the problem assuming that M is the mass of the whole pulley that consist of two disk-form parts of the same thickness, made of the same material. Usually the problem writers think in 2D where thickness does not exist.:wink:

ehild
 
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