91Ó°ÊÓ

A vector is entities that describe the magnitude as well as the direction of quantity.

Vector tells us about the direction of the entity; if we want to show the opposite direction of any reference vector, then a negative sign is used.

Part (a)

A negative vector is a vector that shows its direction with reference to another positive direction vector.

Part (b)

For example, if$\overline{PQ}$is some vector in a particular direction and if we want to show another vector of the same magnitude but in the opposite direction, we will represent it as a negative vector of PQ, i.e.,$-\overline{PQ}$,

$\overline{PQ}=-\overline{PQ}$

Yes, it is absolutely correct that one vector is negative with respect to the other, as a negative vector defines nothing but direction. If one vector is in the opposite direction to another one, it is said to be a negative vector.