When a vector
is multiplied by a real number, say l, then we get another vector l
. The magnitude of l
is l times the magnitude of
. If l is positive, then the direction of l
is the same as that of
. If l is negative, then the direction of l
is opposite to that of
.
is multiplied by zero, we get a vector whose magnitude is zero and whose direction is arbitrary. This vector is called a zero vector or null vector.
If l is a pure number and has no units, then the units of l
are the same as those of
. But, if the scalar has a certain unit, then the unit of l
will be different from that of
.
Example
- The multiplication of velocity vector by time (a scalar) gives us displacement.
- The multiplication of velocity vector by mass (a scalar) gives us momentum.
