Essentially all of the quantities we encounter in Physics -- certainly all that we will see in this course -- may be classified as scalars or vectors.
A quantity is a scalar if it is fully specified by a number and a unit. A few examples are
37o C or 99o F
However, some quantities require more information.
A quantity is a vector if it is fully specified by a number, a unit -- and a direction. A few examples are
5.3 km, due North
2.34 m/s, 30o W of N
9.8 m/s2, downward
1.234 kg-m/s, to the right
6.7 N/C, 60o E of N
(C) 2003, Doug Davis; all rights reserved