WAEC Physics 2021 Paper

Concept:A vector quantity needs both magnitude and direction for its full description, while a scalar has only magnitude.Explanation:A vector is completely described only when its magnitude and direction are stated.Force $\vec{F}$ has magnitude and acts in a definite direction, so it is a vector.Displacement $\vec{s}$ measures the straight-line change of position and also has direction, so it is a vector.Momentum is defined as $\vec{p} = m\vec{v}$, and since velocity $\vec{v}$ is a vector, momentum is also a vector.In option A, pressure and energy are scalars, while force is a vector.In option C, distance and work are scalars, while acceleration is a vector.In option D, density and volume are scalars, while weight $m\vec{g}$ is a vector.Hence, only the set containing force, displacement, and momentum has all members as vectors.Answer:B. Force, displacement and momentum