# Modulus of Elasticity

• I
Sudarsan
Which modulus define a property of fluids??

The above mentioned question was asked in my college internals. The answer they suggested was sheer modulus.
Any explanations??

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I would have been more inclined to say the bulk modulus that describes compressibility.

Sudarsan
I would have been more inclined to say the bulk modulus that describes compressibility.
That was my answer, but they didn't accept it..

Oh, well, what can I say?

Sudarsan
Oh, well, what can I say?
They said flow of fluids related to sheer modulus. I can't understand even a single bit of that, I don't know how flow of fluids can be compared with Elasticity

Mapes
Homework Helper
Gold Member
Fluids have zero shear modulus, so fluid flow can be driven by an arbitrarily small shear stress. In this way, the shear modulus (or lack thereof) does define fluids, and the flow of fluids is indeed "related" to the shear modulus. But the question is vague. The bulk compressibility also characterizes the mechanical response of fluids, of course.

An analogous question might be: What electrical material property defines a superconductor? Answer: The conductivity (infinite) or resistivity (zero).

Sudarsan
Chestermiller
Mentor
They said flow of fluids related to sheer modulus. I can't understand even a single bit of that, I don't know how flow of fluids can be compared with Elasticity
It's a stupid question, but I would have answered viscosity (which describes the shear-stress/shear-rate behavior of fluids.

sophiecentaur