Figure 12.1: An inertial frame and a moving frame

1. Inertial Coordinates, designated by grey x, are presented with supercript I and subscripts: 1, 2, 3
2. Inertial frame is presented with supercript I on the base vectors and subscripts: 1, 2, 3
3. Moving Body Coordinates, designated by grey s, are presented with supercript (a) and subscripts: 1, 2, 3
4. Moving frame is presented with supercript (a) on the base vectors and subscripts: 1, 2, 3