I offer this nitpick about non-computer issues to the monestary in the interests of academic completeness.
Within an engineering community, stress and strain have an exact meaning (stress => compression, strain => tension), and people who misuse the terms brand themselves as weenies. Or, at least, non-engineers.

Non-engineer, definitely. :) Strain can be thought of as a measure of movement, and stress as a measure of force. Your example sounds to me like you're saying "I weigh 17 inches." - nonsense. So here's a mini-tutorial on stress, strain, and the like, because I know you're dying to learn about solid mechanics today.

Stress is essentially a measure of how much force exists in a unit area of something - a basic expresion is s=p/a (though stress should be written sigma - σ). Stress can be thought of as pressure. Take a pencil, put the point down on your desk, and press on the eraser head - it doesn't hurt. Would it hurt if you had the eraser head on the desk and your palm was pressing against the pencil lead? There is less pencil area for the force of your hand to act on, so the stress is higher. (BTW, if you really want me to, I can explain bending stresses (s=M*c/I) as well.)

Strain is a measure of the change of length of something - expressed as e=change/length (and e should be written epsilon - ε). If I have a spring which is an inch long, and I compress it, it may change length .5 inches. If I take a spring which is 10 inches long, but otherwise identical, and I compress it, I'll get much more length change than .5 inches. Strain is a ratio measure of length change.

A reason that lay-people often use the terms interchangably is that the two are related. Hook's law is an empirical relationship which states that stress and strain are directly related : s=e*E (or σ=ε*E for those browsers which support HTML entities). The constant 'E' is Young's Modulus, also called the Modulus of Elasticity; you can think of it as a measure of how much force it takes to compress a spring, the two concepts are very close.

I don't know what jmcnamara meant when he offered up his example - I'll assume that he knew what stress and strain are. So now you know a little about solid mechanics.

In reply to Nitpick about Re: Re: What is the difference between a corner case and edge case? by Louis_Wu
in thread What is the difference between a corner case and edge case? by FamousLongAgo

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.