Minimum Diameter for Steel Wire: Solve It Now

AI Thread Summary
A circular steel wire measuring 1.91m must not stretch more than 0.0024m under a tensile force of 450N. The discussion revolves around calculating the minimum diameter required for the wire, with participants struggling to arrive at the correct solution. Initial attempts to apply volume equations and stress formulas were unsuccessful, leading to suggestions to consider Young's Modulus. One participant claimed to have calculated a diameter of 2.1mm, but this was deemed incorrect by others. The conversation emphasizes the need for careful re-evaluation of calculations and parameters involved in the problem.
asleight
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Homework Statement



A circular steel wire 1.91m long must stretch no more than 0.0024m when a tensile force of 450N is applied to each end of the wire.

What minimum diameter is required for the wire?

Homework Equations



p=\frac{F}{\Delta A}

The Attempt at a Solution



I can't seem to solve for this at all. I've tried applying a volume to this exercise:

A=V/l, where l is the length, then dA=\sqrt{dV/l-Vdl/l^2}...

p=\frac{F}{\Delta A}=\frac{F}{\sqrt{dV/l-Vdl/l^2}}. This didn't work, as far as I remember...
 
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asleight said:

Homework Statement



A circular steel wire 1.91m long must stretch no more than 0.0024m when a tensile force of 450N is applied to each end of the wire.

What minimum diameter is required for the wire?

Homework Equations



p=\frac{F}{\Delta A}

The Attempt at a Solution



I can't seem to solve for this at all. I've tried applying a volume to this exercise:

A=V/l, where l is the length, then dA=\sqrt{dV/l-Vdl/l^2}...

p=\frac{F}{\Delta A}=\frac{F}{\sqrt{dV/l-Vdl/l^2}}. This didn't work, as far as I remember...

Perhaps you want to look at Young's Modulus for the wire?

http://hyperphysics.phy-astr.gsu.edu/hbase/permot3.html#c2
 
I solved and got 2.1mm...

It's not correct.
 
asleight said:
I solved and got 2.1mm...

It's not correct.

It's not what I got either.

Maybe re-check your numbers?
 
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