Looking for classes? Ksquare Career Institute, Bengaluru →
For which angle between two equal vectors $\vec{A}$ and $\vec{B}$ will the magnitude of the sum of two vectors be equal to the magnitude of each vector?
Explanation
$|\vec{A} + \vec{B}| = \sqrt{A^{2} + B^{2} + 2AB \cos 120^{\circ}} (\theta = 120^{\circ})$ = $\sqrt{A^{2} + B^{2} + 2AB( - 1/2)} (\cos 120^{\circ} = -1/2)$ = $\sqrt{A^{2} + B^{2} - A(A)} = \sqrt{B}^{2} = B ( \because A = B)$