Definition 1 A quantity that has magnitude as well as direction is called a vector Notice that a directed line segment is a vector (Fig 10 1(iii)), denoted as AB
uuur
 or
simply as ar , and read as ‘vector AB
uuur
’ or ‘vector ar ’ The point A from where the vector AB
uuur
 starts is called its initial point, and the
point B where it ends is called its terminal point