Cutting a Copper Wire for Different Resistances

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Homework Help Overview

The discussion revolves around a physics problem involving the resistance of a copper wire and determining the point at which it should be cut to achieve specific resistance ratios between the two pieces.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to apply the resistivity formula and manipulate it to find the lengths and resistances of the wire pieces. Some participants suggest considering the relationship between the lengths of the wire segments and the total length.

Discussion Status

The discussion is ongoing, with participants providing hints and suggestions for approaching the problem. There is an exploration of different interpretations of the equations and relationships involved, but no consensus has been reached on a specific method to resolve the issue.

Contextual Notes

Participants are navigating the constraints of the problem, including the total resistance of the wire and the requirement that one piece's resistance is four times that of the other. There is uncertainty regarding the correct application of the equations related to the lengths and resistances.

DevilishNole
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I need help with one of my Physics homework problems please!

A certain copper wire has a resistance of 10.0 Ohm. At what point along its length must the wire be cut so that the resistance of one piece is 4.0 times the resistance of the other? What is the resistance of each piece?

I worked it out and got that R=2 Ohm, and so the other piece, 4R, has to be equal to 8 Ohm. I used the equation for resistivity, R= rho*L/A using 4R in the place of R and solved for L. I replaced this back into the original equation but end up in a loop, with R=2. I have no idea what I'm doing wrong; can anyone please help?!
 
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You need to use the fact that L1 + L2 = Ltotal.
 
I did that on my second attempt to the problem but to no avail because I do not know when to use the "L1+L2" equation and the "Ltotal"
 
Consider it as a proportion.
 

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