# Homework Help: Yield Strength

1. Nov 29, 2004

### SnowOwl18

This one is confusing me:

-----The yield strength of a material is the largest stress a material can support without permanently elongating (like a slinky stretched too far). A brass wire 2.10m long is to support a 176.00N "Eat At Joe's" sign without permanently elongating. The wire is made of a variety of yellow cold-rolled brass that has a yield strength of 4.75×108Pa. What minimum diameter wire is called for?----

I'm not sure what type of equation I could use to solve this problem...I'm just kinda lost. Any guidance would be awesome. Thanks :)

Last edited: Nov 29, 2004
2. Nov 29, 2004

### PerennialII

You could start by thinking about normal stresses in the wire (which in this case behaves as a rod), with respect to yield strength information about Hooke's law is handy in explaining the concept of the problem further (eat at Joe's sign ... someone has been creative .... :rofl: ).

3. Nov 30, 2004

### Gokul43201

Staff Emeritus
Surely they tought you what stress is before giving you problems like this ?

How is stress defined ?

4. Nov 30, 2004

### SnowOwl18

Yes, my teacher is a creative one ;)

Stress and pressure are F/A. Someone was trying to help me with the problem and he said to use the equation : F/A = Yield (Delta L/ L initial)....sort of like the setup using Young's modulus. So I was trying to solve for area so that I could find the diameter of the wire, but I don't know what the change in length would be. Am I going about this correctly? Thanks for the help so far :)