Calculating Tension for Beginners

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Homework Help Overview

The discussion revolves around calculating the tension in wires supporting a street lamp, which weighs 150N. The problem involves understanding the forces acting on the lamp and how to resolve them, particularly when the angle between the wires changes.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants suggest drawing a free body diagram and resolving the tension into components. There are questions about the equilibrium of forces and how to apply these concepts to find the tension in the wires.

Discussion Status

The discussion includes various attempts to guide the original poster towards understanding the problem. Some participants express frustration with the lack of clarity in the teaching materials, while others emphasize the importance of understanding the concepts rather than just finding the answer.

Contextual Notes

The original poster expresses difficulty with the problem due to perceived inadequacies in teaching and the complexity of the textbook explanations. There is a mention of the need for formulas, which the poster feels unprepared to provide.

WakeOfBeauty
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My teacher is a dumbass and a horrible teacher. I swear he never taught us how to find tension and the "textbook" gives us long stories about little Billy and Bobby but never explains how to DO the problems. I need help for this question. Please explain if you can


Homework Statement



A street lamp weighs 150N. Its supported by two wires that form an angle of 120 degrees with each other. The tension in the wires are equal.
a) what is the tension in each wire supporting the street lamp?
b) If the angle between the wires is reduced to 90 degrees, what is the tension in each wire?

2. Formulas Needed

no clue. sorry

3. Attempts
I don't know any of this so I couldn't even attempt to do it. I don't know where to even start
 
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Draw the free body diagram with all the forces acting. Then split then tensions in the wires into x and y components. Then use the fact that for equilibrium, the sum of the forces in a specified direction is zero.
 
Welcome to PF.

Maybe you shouldn't be so hard on your teacher? At least the teacher likely knows how to figure the problem?

But as to equations this is a matter of resolving the force vectors from the information given. Drawing a diagram should be helpful.

You know what the vertical components of the tension must be in the two lines, hence you should be able to figure the Tension itself.
 
this doesn't help at all.
 
https://www.physicsforums.com/showpost.php?p=1042781&postcount=2
 
'kay, i figured it out on my own already. bye :)
 
That's great. The system works and you learned how to solve the problem.

If someone had told you the answer you might have difficulty come exam time.
 

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