Question

If magnitude of resultant of two forces F and F are acting at a point F then the angle between forces is:

A)0 B)60 C)120

Answer 1

$$\begin{gathered} Given{F}_1=F \\ {F}_2=F \\ Resul\tan t,F_R=F \\ {F}_R=\sqrt{{F_1}^2+{F_2}^2+2F_1{F}_{2}Cos\theta } \\ F=\sqrt{F^2+F^2+2F^{2}Cos\theta } \\ Cos\theta =-\frac{1}{2} \\ \theta =120° \end{gathered}$$Let F1 = FF2 = 2FFR = Let F1 = FF2 = 2FFR