The product of a number
m by a vector
![](gif/vec_u.gif)
is the vector
![](gif/vec_mu.gif)
that it has:
1) direction: The same one that
if m is positive
Opposite to
if m is negative
2) module: the module of
multiplied by the absolute value of m
If m =0 the vector
null vector, is one vector that has module and that one indicates by
. That is to say,0
=
.
Summarizing, to multiply a vector by a number m being equivalent to lengthen (or shrinking) his module as many times as he indicates the absolute value of m, and reverse its direction if m is negative.
The number m by which a vector multiplies one receives the name of scalar.
In the figures of the right you have three examples of a product of a scalar one a vector.