what is hooke's law?

Question

bhla blah blah................

Answer 1

This is a law in physics and engineering,

An elastic bar of length L and cross section area A is stratched by a force P, then
axial stress = Force/area = P/A
axial Strain = Elongation/Length, d/L
Hooke's Law says:
Axial Stress is proportional to axial strain
P/A = E d/L
E, the propotional constant, is young's modulus

d = PL/(AE)

http://en.wikipedia.org/wiki/Hooke's_law

Answer 2

In physics, Hooke's law of elasticity is an approximation that states that the amount by which a material body is deformed (the strain) is linearly related to the force causing the deformation (the stress). Materials for which Hooke's law is a useful approximation are known as linear-elastic or "Hookean" materials.

Hooke's law is named after the 17th century British physicist Robert Hooke. He first stated this law in 1676 as an anagram, then in 1678 in Latin as Ut tensio, sic vis, which means:

“ As the extension, so the force. ”

For systems that obey Hooke's law, the extension produced is directly proportional to the load:

F = - k x(sorry! I couldn't get the real one, so I had to use this)
where

x is the distance by which the material is elongated [usually in meters],
F is the restoring force exerted by the material [usually in Newtons], and
k is the force constant (or spring constant). The constant has units of force per unit length [usually in Newtons/metre].
When this holds, we say that the behavior is linear. If shown on a graph, the line should show a direct variation.

Answer 3

In it's basic form in elasticity is:

S(ij)=E(ijkl)e(kl) written as a fourth order tensor (Timoshenko or Sokolnikoff "Theory of Elasticity")
It is the relation between stress and the strain in a solid
The stress is the specific force per unit area applied
The strain is the dilatation (elongation or contraction) of a certain "gage length"
Simple way to look at strain is to use a rubber band. Mark two dots one inch apart and call that your gage length Lo, stretch the rubber band to a length Lf (Lf>Lo,) then the strain is defined as the change in length divided by the original length ( or (Lf-Lo)/Lo. Note that strain is independent of dimensions (inches/inch, cm/cm) and can usually be expressed as a percent of the original length.
For most solids which are considered isotropic (same properties in all 3 perpendicular directions) Hooke's law can be simplified to
S= E*e, where E is the Elastic or Young Modulus of the material, e is the strain, and S is the applied stress. Note again that both stress and Modulus have the same units (force per unit area) either lbs/sq inch or N/sq meter or equivalent units

Answer 4

I'm surprised a botonist is looking for this info, are you waving the wrong flag? Anyway, for a SPRING that is moderately stressed (either compressed or expanded), the distance from a non-stressed length is proportional to the force applied, the proportionality constant called Hooke's constant.

Answer 5

F=kx.

It means that the force you apply to an elastic object is directly proportional to the "strain" it will experience. Eg: if you apply 10 newtons to something and it stretches 5 m, applying 20 newtons will stretch it 10 meters.