Equilibrium Tension Along a Curved String

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Homework Help Overview

The problem involves a light inextensible string hanging on two pegs between parallel walls, with a frictionless pulley attached to a block. The objective is to determine the tension in the string when equilibrium is established after the pulley runs along it.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to analyze the tension in the string by considering the angles made by the tension force at the pulley and equating vertical components to the weight. Some participants question the length between the walls and suggest that more detailed working should be provided for clarity.

Discussion Status

The discussion has seen some productive exchanges, with participants offering hints about geometric relationships and encouraging the original poster to clarify their working. There is acknowledgment of the need for more information to fully understand the setup.

Contextual Notes

There is a mention of an unknown variable h and the need to express angles in terms of given lengths, indicating potential constraints in the information provided. The original poster's initial attempt does not yield a complete expression for tension, suggesting further exploration is needed.

Raghav anand
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IMG_0894.JPG

Homework Statement


A light inextensible string of length l hangs on two pegs attached to parallel walls separated by a height. A small frictionless pulley of weight Wp is attached to a block of weight Wb. When it is placed on the string, the string becomes taut and pulley runs on the string till equilibrium is established. What is the tension in the string?

Homework Equations


F=ma; vertically and horizontally
x, l, Wp, Wb are the given variables

The Attempt at a Solution


The angles the tension force makes with the pulley at the point of contact are equal as the horizontal components of tension are equal. When equating the vertical component to mg, I only get an expression for T in terms of an unknown variable h. I eliminated y by using the two triangles marked in the diagram. Any thoughts?
 
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What is the length between two walls?
 
Raghav anand said:
[
The angles the tension force makes with the pulley at the point of contact are equal as the horizontal components of tension are equal. When equating the vertical component to mg, I only get an expression for T in terms of an unknown variable h. I eliminated y by using the two triangles marked in the diagram. Any thoughts?
I gather the distance between the walls is x.
You should post more of your working, preferably typed, not as an image.
You should be able to find the angle in terms of l and x only - it's just geometry. Hint: project the line of one side of the string down until it reaches the opposite wall. After that it is straightforward.
 
I will make sure to write more from next time. Got the answer, thanks!
 

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