At what angle must the two forces $(x + y)$ and $(x -y)$ act so that the resultant may be $\sqrt {({x^2} + {y^2})} $
${\cos ^{ - 1}}\left( { - \frac{{{x^2} + {y^2}}}{{2({x^2} - {y^2})}}} \right)$
${\cos ^{ - 1}}\left( { - \frac{{2({x^2} - {y^2})}}{{{x^2} + {y^2}}}} \right)$
${\cos ^{ - 1}}\left( { - \frac{{{x^2} + {y^2}}}{{{x^2} - {y^2}}}} \right)$
${\cos ^{ - 1}}\left( { - \frac{{{x^2} - {y^2}}}{{{x^2} + {y^2}}}} \right)$
The vectors $\vec{A}$ and $\vec{B}$ are such that
$|\vec{A}+\vec{B}|=|\vec{A}-\vec{B}|$
The angle between the two vectors is
Explain the parallelogram method for vector addition. Also explain that this is comparable to triangle method.
Two forces with equal magnitudes $F$ act on a body and the magnitude of the resultant force is $F/3$. The angle between the two forces is