Physics help on pulleys and tension

In summary, the conversation discusses a system involving a pulley with a radius R1 and rotational inertia I1, connected to two blocks of mass m via a light cord. The tension T in the cord is determined, as well as the tension T3 in the cord when one block is removed and the system is released from rest. The rotational inertia of the pulley is also determined. Then, the conversation moves on to a new system where the cord is tied into a loop and passed around a larger pulley with a radius 2R1 and rotational inertia 16I1. The angular speed, angular momentum, and total kinetic energy of the system are determined in terms of fundamental constants and given values.
  • #1
princess_7777
3
0
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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  • #2
You need to show your work before you get help. What have you done with this question?
 
  • #3
well for (a) i tried it by using the equation and got 42,129.91
ii.: 6,006.23
 
  • #4
The answer to all the questions is [itex]\pi[/itex].
 
  • #5
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.
 

What is the purpose of a pulley?

A pulley is a simple machine that is used to lift or move heavy objects by changing the direction of the force applied. It can also reduce the amount of force needed to lift an object, making it easier to move.

How does a pulley work?

A pulley works by using a wheel with a groove or channel around its circumference. A rope or belt is run through the groove and attached to an object. When the rope is pulled, the object is lifted or moved. The pulley changes the direction of the force, making it easier to lift the object.

What is tension in relation to pulleys?

Tension is the force that is transmitted through a rope or cable when it is pulled tight. In a pulley system, tension is used to lift or move objects by applying force to the rope or belt that runs through the pulley.

How do I calculate the tension in a pulley system?

The tension in a pulley system can be calculated using the formula T = P x (R/D), where T is the tension, P is the weight of the object being lifted, R is the radius of the pulley, and D is the distance between the pulley and the object being lifted.

What are some real-world applications of pulleys?

Pulleys are used in a variety of real-world applications, such as elevators, cranes, and zip lines. They are also used in everyday items like window blinds, flagpoles, and exercise equipment. Pulleys are also commonly used in physics experiments to demonstrate concepts such as force, motion, and mechanical advantage.

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