Message-Id: <v01540b0bb0b641b905b2@[192.174.2.173]>
Date: Thu, 11 Dec 1997 18:35:35 -0800
To: pinhole@exploratorium.edu
From: pauld@exploratorium.edu (Paul Doherty)
Subject: Re: Vectors
Actually area can be a vector.
The magnitude of the area vector is its area
the direction is perpendicular to the (planar) area called the normal vector.
Of course there are two directions to choose from, and the rule is, if the
area surrounds a closed region pick the outward one.
Hydrostatic pressure on an area creates a force which is a vector.
The direction of the force vector is normal to the area.
If a parallelogram area has two sides meeting at a vertex, then the area of
the parallelogram is the vector cross product of the two vectors
representing the sides. The vector cross product is a vector and so is the
area.
This is one use of the vector cross product.
Paul Doherty