Question

Two vectors A and B are such that A =1,B=2,A.B=1 find angle

Answer 1

Answer:$60^{\circ}$

Explanation:

Given

$\mid\Vec{A}\mid=1$

$\mid\Vec{B}\mid=2$

And $A\cdot B=1$

We know $\vec{A}\cdot \vec{B}=\mid\Vec{A}\mid\mid\Vec{B}\mid\cos \theta$

Where $\theta$ is the angle between them

Substituting the values

$1=1\times 2\cos \theta$

$\cos \theta =\dfrac{1}{2}$

$\theta =60^{\circ}$

Thus the angle between $A$ and $B$ is  $60^{\circ}$