When A. B = - |A||B|, then - Vidyadip

MCQ

When $\vec A.\vec B = - |A||B|,$ then

A
$\vec A$ and $\vec B$ are perpendicular to each other
B
$\vec A$ and $\vec B$ act in the same direction
✓
$\vec A$ and $\vec B$ act in the opposite direction
D
$\vec A$ and $\vec B$ can act in any direction

✓

Answer

Correct option: C.

$\vec A$ and $\vec B$ act in the opposite direction

c
(c) $\overrightarrow A .\overrightarrow B = AB\cos \theta $

In the problem $\overrightarrow A .\overrightarrow B = - AB$ i.e. $\cos \theta = - 1$

$\theta = 180^\circ $

i.e. $\overrightarrow A $ and $\overrightarrow B $ acts in the opposite direction.

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