Is it possible to do this without Poission's ratio?

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SUMMARY

The discussion centers on solving a problem involving a steel alloy bar with a modulus of elasticity of 205 GPa, which experiences elastic deformation when a force is applied. The task is to determine the force required to achieve a 0.003mm diameter reduction without explicitly using Poisson's ratio. Participants conclude that while Poisson's ratio is typically necessary for such calculations, assuming a value of 0.3 allows for the application of relevant equations, including stress, strain, and Hooke's law.

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Nodnarb98
this is the problem as our professor gave it to us

"A steel alloy bar (modulus of elasticity of 205 GPa) is 20mm in diameter and experiances an
elastic deformation by applying a force along its axis (IE pulling it apart perpendicular to the
circular cross section). Determine the force needed to cause a .003mm diameter reduction."
is it even possible to do the problem without the ratio? if so where do I start?

2. Homework Equations I Know stress =f/a, and strain = Δl/l and hooke's law σ=Eεz. as you can see he didn't give us possion's ratio, used in εz=-εx/v.

The Attempt at a Solution


I've tried setting it up multiple ways, but each time i have more unknowns that equations. I emailed my instructor but he hasn't answered

Thanks!
 
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In my judgment, you need to know Poisson's ratio. Assume 0.3
 
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Thanks
 

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