Question

Two forces, each of magnitude $F$ have a resultant of the same magnitude $F$. The angle (in $degrees$) between the two forces is

Answer 1

Given,two force of equal magnitude $=F$
and the resultant of these forces $=F$
$\Rightarrow F=\sqrt{F^2+F^2+2F^2\cos \theta }$

$F^2=2F^2(1+\cos \theta )$
$\Rightarrow \cos \theta =-\frac{1}{2}$
$\theta ={120}^{\circ }$
Final answer:${120}^{\circ }$