The resultant of two vectors A and vector B is perpendicular to vector A and its magnitude is half that of vector B .

Question

The resultant of two vectors \(\vec{A}\) and \(\vec{B}\) is perpendicular to \(\overrightarrow{\mathrm{A}}\) and its magnitude is half that of \(\vec{B}\). The angle between vectors \(\vec{A}\) and \(\vec{B}\) is ............

Answer 1

Correct answer is : 150  

\(\mathrm{B} \cos \theta=\frac{\mathrm{B}}{2}\)

\(\Rightarrow \theta=60^{\circ}\)

So, angle between \( \overrightarrow{\mathrm{A}} \ \&\ \overrightarrow{\mathrm{B}}\) is \(90^{\circ}+60^{\circ}=150^{\circ}\)