# ^^Grandezze scalari e vettoriali.

- grandezza scalare assoluta, cioe' senza segno
- grandezza scalare relativa, cioe' con segno
- grandezza vettoriale

# Approfondimento

## Scalars and Vectors.

From:
The dynamics of particles and of rigid, elastic, and fluid bodies. Being lectures on mathematical physics (1912) Webster, Arthur Gordon, 1863-1923

In mathematics we have to consider two sorts of quantities,

- those which do
not involve the idea of direction, called by Hamilton scalars (
*because they may
be specified by numbers marked off on a scale*),
- and those which do, called steps
or vectors.

The distance between two points x_{1}, y_{1}, z_{1},
x_{2}, y_{2}, z_{2}

s = √ ( (x_{2} - x_{1})^{2} + (y_{2} - y_{1})^{2}
+ (z_{2} - z_{1})^{2} )

is a scalar, whereas the geometrical difference in position of the two points is
known only when we specify not merely the length, but also the direction of the
line joining them.