Plumb line

Encyclopedia : P : PL : PLU : Plumb line

---

"Plumbline" redirects here. For , see .

A plumb line is a reference line guided by a string or cord weighted at the end with a large weight known as a plumb bob. It is used to create a vertical reference line, where a spirit level may be impractical or difficult to use.

The line has in every point the same direction as that of the force of gravity of the Earth; thus, an object dropped on the surface of the Earth tends to follow this line.

Strictly speaking the plumb line is not straight: it is curved mainly in the North-South direction (approximately 0.2" per km of elevation). This is mathematically connected with the fact that gravity diminishes when going from pole to equator. The curvature is additionally affected by rough topography.

See also

• vertical
• zenith
• vertical deflection

External links

• [The definitions of plumb line]

 

---

From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.

Search Titles

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

?