# Archimedes to Hawking: Laws of Science and the Great Minds behind Them

By Clifford A. Pickover | Go to book overview

HOOKE’S LAW OF ELASTICITY

England, 1660. The size of a material deformation is directly proportional to the deforming force.

CROSS REFERENCE: NEWTON’S LAW OF UNIVERSAL GRAVITATION AND BOYLE’S GAS LAW.

During the year that Hooke discovered his law, Dutch peas-
ants (Boers) settled in South Africa, and water closets arrived
in England from France. The Irish natural philosopher Robert
Boyle described his research showing that the removal of air
from a chamber extinguishes a flame and kills small animals,
which suggested that combustion and respiration may be related
processes.

Hooke’s Law of Elasticity states that if an object, such as a metal rod or spring, is elongated by some distance, x, the restoring force F exerted by the object is proportional to x:

Here, k is a constant of proportionality that is often referred to as the spring constant when Hooke’s Law is applied to springs. Hooke’s Law is an approximation that applies for certain materials, such as steel, which are called Hookean materials because they obey Hooke’s Law under a significant range of conditions. For other materials, such as aluminum, Hooke’s Law has a more restricted use that applies only to a portion of the elastic range of the material. Rubber objects are non-Hookean because of their very complex responses to applied forces. For example, the stiffness of rubber is very sensitive to temperature and the rate at which a force is applied.

Students most often encounter Hooke’s Law in their study of springs where the law relates the force F, exerted by the spring, to the distance x that the spring is stretched. The spring constant k is measured in force per length. The negative sign in F = –kx indicates that the force exerted by the spring opposes the direction of displacement. For example, if we were to pull the end of a spring to the right, the spring exerts a “restoring” force to the left. The displacement of the spring refers to its displacement from equilibrium position at x = 0.

The spring constant provides an indication of the stiffness of the spring. A large value for k indicates that the spring is stiff, whereas a low value for k means that the spring is loose. As another example, consider a mass hanging from a spring. The initial position of the end of the spring is

-74-

If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes

#### Cited page

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

#### Cited page

Archimedes to Hawking: Laws of Science and the Great Minds behind Them

Settings

#### Settings

Typeface
Text size Reset View mode
Search within

Look up

#### Look up a word

• Dictionary
• Thesaurus
Please submit a word or phrase above.

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this book
• Bookmarks
• Highlights & Notes
• Citations
/ 514

### How to highlight and cite specific passages

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

## Cited passage

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

## Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.