alleryIf $\vec{PQ} = \vec a$, then $\vec{QP}$ equals:
A$\vec a$
B$-\vec a$
C$2\vec a$
D$\vec 0$
Answer & Solution
Correct answer: B. $-\vec a$
**Reversing direction reverses sign:** $\vec{QP} = -\vec{PQ} = -\vec a$.
Same magnitude, opposite direction.
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