Vectors and scalars | Improve Society

There are quantities in physics characterized by both magnitude and direction, such as displacement, velocity force and acceleration. To describe such quantities, we introduce the concept of a vector as a directed line segment $\overrightarrow{PQ}$ from one point P called the initial point to another point Q called the terminal point. We denote vectors by bold faced letters or letters with an arrow over them. Thus $\overrightarrow{PQ}$ is denoted by $\bold A$ or $\vec{A}$ . The magnitude or length of the vector is then denoted by $|\overrightarrow{PQ}|$ , $\overline{PQ}$ , $|\bold{A}|$ or $|\overrightarrow{A}|$ .

Other quantities in physics are characterized by magnitude only, such as mass, length and temperature. Such quantities are often called scalars to distinguish them from vectors, but it must be emphasized that apart from units such as feet, degrees, etc., they are nothing more than real numbers. We can thus denote them by ordinary letters as usual.