Question

Two equal forces act a point. The square of their resultant is three times their product of magnitudes. The angle between them is

• A. ${30}^{\circ }$
• B. ${60}^{\circ }$
• C. ${90}^{\circ }$
• D. ${120}^{\circ }$

Answer 1

The correct option is B ${60}^{\circ }$

We have
$F^2+F^2+2F^{2}cos\theta =3F^2$
$cos\theta =\frac{1}{2}$
$\theta ={60}^{\circ }$