In classical mechanics, a central force on an object is a force whose magnitude only depends on the distance r of the object from the origin and is directed along the line joining them:
where is the force, F is a vector valued force function, F is a scalar valued force function, r is the position vector, ||r|| is its length, and = r/||r|| is the corresponding unit vector.
Equivalently, a force field is central if and only if it is spherically symmetric.
Read more about Central Force: Properties, Examples
Famous quotes containing the words central force, central and/or force:
“For us necessity is not as of old an image without us, with whom we can do warfare; it is a magic web woven through and through us, like that magnetic system of which modern science speaks, penetrating us with a network subtler than our subtlest nerves, yet bearing in it the central forces of the world.”
—Walter Pater (1839–1894)
“There is no such thing as a free lunch.”
—Anonymous.
An axiom from economics popular in the 1960s, the words have no known source, though have been dated to the 1840s, when they were used in saloons where snacks were offered to customers. Ascribed to an Italian immigrant outside Grand Central Station, New York, in Alistair Cooke’s America (epilogue, 1973)
“The force that through the green fuse drives the flower
Drives my green age; that blasts the roots of trees
Is my destroyer.
And I am dumb to tell the crooked rose
My youth is bent by the same wintry fever.”
—Dylan Thomas (1914–1953)