# Physical meaning of curl

hi

whats's the physical meaning of curl?

and why it is a vector?
it's definition is line integral per volume. i can't understand why this is a vector.

HallsofIvy
Homework Helper
First, my usual proviso- there is no one "physical" meaning to a mathematical concept. But there are specific applications and perhaps a "most important" or "most common" application.

In particular, we can apply the curl of a vector to fluid motion- if $v(x, y, z)$ is the velocity vector of water, say, so that v is depends on the position but not time, the $curl v= \nabla\times v$ describes the "rotation" of the fluid. It is a vector because its direction shows the axis about which the fluid rotates while its length is the speed of rotation.

arildno