# Comparing the toughness of materials

shk
Homework Statement:
solid properties
Relevant Equations:
Tension=Force/Area
stress strain graph
compressive force
UTS
tough and elastic materials
I need some help with the question that I have attached.
I think I should say that the beef burger is tough and brittle but the tooth wrenching is not tough but it's elastic .
or maybe it's tough and elastic.
basically the beef won't have plastic deformation but the tooth wrenching has.
generally I'm not sure how to answer the question.

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Homework Helper
I think I should say that the beef burger is tough and brittle but the tooth wrenching is not tough but it's elastic .
What does "tough" mean in a physics context?
What does "brittle" mean in a physics context?
What does "elastic" mean in a physics context?

Before we can ask whether a beef burger fits those adjectives, we need to know what those adjectives mean.

shk
shk
What does "tough" mean in a physics context?
What does "brittle" mean in a physics context?
What does "elastic" mean in a physics context?

Before we can ask whether a beef burger fits those adjectives, we need to know what those adjectives mean.

This is what I know :

Brittle material is a material that breaks with a small elastic deformation and almost no plastic deformation. It can be strong or weak.

A tough material is a strong and ductile material. I mean it's something eith great breaking strain and large plastic deformation. The way that the area under the strain stress graph is big.

Hope this was all that you wanted me to say.
I look forward to your help.
Thanks

Delta2
Homework Helper
This is what I know :

Brittle material is a material that breaks with a small elastic deformation and almost no plastic deformation. It can be strong or weak.

A tough material is a strong and ductile material. I mean it's something eith great breaking strain and large plastic deformation. The way that the area under the strain stress graph is big.

Hope this was all that you wanted me to say.
I look forward to your help.
Thanks
You have said that you think that a beef burger is brittle. Yet in my experience the only ones I've seen shatter when struck have been frozen. Even those don't shatter well.

shk, Delta2 and Tom.G
shk
You have said that you think that a beef burger is brittle. Yet in my experience the only ones I've seen shatter when struck have been frozen. Even those don't shatter well.
Thank you.
Ok then so beef burger isn't brittle. It's tough . Can I add any other words for beef burger ? Can I say it's hard ?
how about the other one . Was it correct?

semenka
The impact strength is the specific work and has a dimension of KGM / cm2. The impact strength depends on the structural state of the steel (for example, on the grain size) and is a very good indicator of the quality of the material.

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the tooth wrenching is not tough but it's elastic .
or maybe it's tough and elastic.
If it's not tough, why was it so hard to bite through?
Does it spring back into shape if released?
the beef burger is tough and brittle
Hard to answer this because there are two materials involved and they behave differently.
We are told the bread falls apart, suggesting a degree of brittleness.
The beef is barely affected, implying both hardness and toughness. It tells us nothing of the brittleness, plasticity or elasticity.

Yet in my experience the only ones I've seen shatter when struck have been frozen.
That would be both hard and brittle. Soft, weak and brittle is also possible.

The style of the question suggests to me that the "correct" answer will be that one or other or both is not tough. Not sure I'd agree.

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Gold Member
The question is to "explain carefully which food is tough in the Salter's syllabus sense." I googled "Salter's syllabus", keeping "sense" out, but the results made no sense and were unsatisfactory considering the question asked. A search on "Salter's scale" was just as fruitless. Can @shk clarify what this scale is or where it can be found?

Last edited:
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The question is to "explain carefully which food is tough in the Salter's syllabus sense." I googled "Salter's syllabus", keeping "sense" out, but the results made no sense and were unsatisfactory considering the question asked. A search on "Salter's scale" was just as fruitless. Can @shk clarify what this scale is or where it can be found?
My assumption is that the Salter reference defines these properties as in post #3. But of course, there is no absolute definition of any of them, so the question should be whether the foodstuffs are tougher or less tough than some specified material.

Mentor
The impact strength is the specific work and has a dimension of KGM / cm2.
What are you trying to list as the units? What is a "KGM"?

It looks like the standard unit for Impact Strength is: $$\frac{kJ}{m^2}$$
https://www.intertek.com/polymers/testlopedia/notched-izod-impact-astm-d256/
ISO impact strength is expressed in kJ/m2. Impact strength is calculated by dividing impact energy in J by the area under the notch. The test result is typically the average of 10 specimens.