Hookes law experiment help

What is hookes law? Are there limitations of hookes law?

 

so now relate that definition of hooke's law to your hypothesis and your observations. Mention its limitations.

 

Analyse the relationship between the conclusion drawn from your data and Hooke's law to verify its validity. Also, is there any anomalies? Do they indicate limitations of Hooke's Law?

 

I recently finished my first course in mechanics (or maybe I should call it physics course A, however...) but we also talked a bit about Hooke's Law. Unfortunately my teacher wasn't a "real" teacher in physics (actually he was a teacher of Mechanical engineering) and it doesn't look like we learnt the "real" Hooke's law, can anyone explain to me what this is then in simple terms?:

σ = Eε

My teacher told us that this (^) was hooke's law. A quick look on wikipedia shows F=-kx, but also I can find σ = Eε if I scroll down a bit.

I know that sigma is the stress caused on a certain area (like the area of the cable holding up an elevator), E is the elastic modulus of a certain material, and epsilon, umm I don't know the word for it in english but I know what it is. :)

Thanks in advance.

 

F = -kx is an equation of motion. Your σ = Eε seems to be more of a definition of materials.

 

The σ=Eε is the general Hooke's law. It may be applied to any piece of elastic material, of any shape. In general all terms are tensors. For the simple case of a bar pulled by the ends with a force F , σ is the force per unit cross section area and ε is the relative elongation.
E is a material constant (Young's modulus).

F=-kx applies to a spring or any elastic object. Here k is a constant of the object and not of just the material. Springs made from the same material may have different values of k, depending on size and shape.

 

Ahhh! Thanks nasu for the good explanation, also I've noticed these "physic" words differ a lot from language to language :b however, big thanks!