1.4.1—The difference between scalar and vector quantities and give examples of

Mass, time, temperature and energy are scalars. Displacement, velocity, acceleration, force and momentum are vectors requiring direction as well as size.

Use scalar arithmetic only for scalars; vector components or geometry are needed when direction changes. A negative signed scalar can represent a component, not a vector by itself.

Speed is the magnitude of velocity; two velocities of 5 m s⁻¹ in opposite directions have equal speeds but a resultant velocity of zero.

A vector is not simply a scalar with an arrow drawn beside it; its direction affects addition and physical effect.