Physics help on pulleys and tension

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Homework Help Overview

The discussion revolves around a physics problem involving pulleys, tension, and rotational inertia. The original poster presents a scenario with multiple blocks and pulleys, requiring the determination of tensions and angular speeds based on given parameters.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore various approaches to calculate the tension in the cord and the effects of changing the system configuration. Some question the original poster's numerical results and seek clarification on the equations and values used.

Discussion Status

The discussion is ongoing, with participants attempting to clarify the original poster's calculations and the methods used. There is a mix of attempts to derive answers and questions about the assumptions made in the problem setup.

Contextual Notes

Participants note the absence of specific numerical values in the problem statement, which may affect the calculations. There are also references to homework rules regarding showing work before receiving assistance.

princess_7777
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2000M3. A pulley of radius R1 and rotational inertia I1 is mounted on an axle with negligible friction. A light cord passing over the pulley has two blocks of mass m attached to either end, as shown above. Assume that the cord does not slip on the pulley. Determine the answers to parts (a) and (b) in terms of m, R1, I1, and fundamental constants.
a. Determine the tension T in the cord.
b. One block is now removed from the right and hung on the left. When the system is released from rest, the three blocks on the left accelerate downward with an acceleration g/3 . Determine the following.
i. The tension T3 in the section of cord supporting the three blocks on the left
ii. The tension Tl in the section of cord supporting the single block on the right
iii. The rotational inertia I1 of the pulley

c. The blocks are now removed and the cord is tied into a loop, which is passed around the original pulley and a second pulley of radius 2R1 and rotational inertia 16I1. The axis of the original pulley is attached to a motor that rotates it at angular speed w1, which in turn causes the larger pulley to rotate. The loop does not slip on the pulleys. Determine the following in terms of I1, RI, and w1.
i. The angular speed w2 of the larger pulley
ii. The angular momentum L2 of the larger pulley
iii. The total kinetic energy of the system

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You need to show your work before you get help. What have you done with this question?
 
well for (a) i tried it by using the equation and got 42,129.91
ii.: 6,006.23
 
The answer to all the questions is \pi.
 
princess_7777 said:
well for (a) i tried it by using the equation and got 42,129.91
ii.: 6,006.23

:confused: By using what equation? What values did you use? I don't see any numerical values given in the question.
 

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