Question

Q2. In the adjoining vector diagram, what is the angle between A and B ?
(Given : C = b/2
(A) 30°
(C) 120°
(B) 60°
(D) 150°​

Answer 1

Answer:

(D) 150

Step-by-step explanation:

sin θ = C/B

sin θ = (B/2)/B

sin θ = 1/2

θ = 30°

Angle between A and B = 180° - 30°

                                        = 150°

Answer 2

Answer:

The angle between vector $\vec_{A}$  and vector $\vec_{B}$  is equal to 30°.

Therefore, the option (A) is correct.

Step-by-step explanation:

Consider that θ is the angle between $\vec_{A}$ and $\vec_{B}$ in a right angle triangle.

The magnitude  of  vector  ${|\vec_{A}|} =a$

The magnitude of ${|\vec_{B}|} =b$

The magnitude of vector  ${|\vec_{C}|} =C =\frac{b}{2}$

We know that,

Sinθ $=\frac{opposite\; side }{Hypotenuse}$

⇒   $sin\theta=\frac{{|\vec_{C}|}}{{|\vec_{B}|}}$

⇒   $sin\theta=\frac{b}{2b}$

⇒   $sin\theta=\frac{1}{2}$

⇒   $sin\theta=sin30^{o}$

∴    $\theta =30^{o}$

Therefore, the angle between vector A and vector B will be 30°.