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.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 3.1 vectors→3.1 vectors — all question types→Physics STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

A man pushes a wall and fails to displace it. He does

How many wavelength of Kr⁸⁶are there in 1m?

If the block $A$ & $B$ are moving towards each other with acceleration $a$ and $b$. Find the net acceleration of $C$.

Vector product of two vectors $2\hat i\, + \,\hat j\,$ and $\hat i\, + \,2\hat j\,$ is

The gravitational force on a body of mass $1.5 \,kg$ situated at a point is $45 \,N$. The gravitational field intensity at that point is ......... $N / kg$

If black wire of platinum is heated, then its colour first appear red, then yellow and finally white. It can be understood on the basis of

A source of sound of frequency $600 Hz$ is placed inside water. The speed of sound in water is $1500 m/s$ and in air is $300 m/s.$ The frequency of sound recorded by an observer who is standing in air is .... $Hz$

The angular speed of a fly-wheel making $120\, revolution/minute$ is

Determine the time in which the smaller block reaches other end of bigger block in the figure. $(g = 10\ m s^{-2})$ .......... $\sec$

A projectile is thrown with some initial velocity at an angle $\alpha$ to the horizontal. Its velocity when it is at the highest point is $(2 / 5)^{1 / 2}$ times the velocity when it is at height half of the maximum height. Find the angle of projection $\alpha$ with the horizontal.