# ABC is an equilateral triangle with O as its centre. F1 , F2 and F3 represent three forces acting along the sides AB, BC and AC respectively. If the total torque about O is zero then the magnitude of F3 is

Q: ABC is an equilateral triangle with O as its centre. $\vec{F_1}$ , $\vec{F_2}$ and $\vec{F_3}$ represent three forces acting along the sides AB, BC and AC respectively. If the total torque about O is zero then the magnitude of $\vec{F_3}$ is

(a) F1 + F2

(b) F1 – F2

(c) (F1 + F2)/2

(d) 2(F1 + F2)

Ans: (a)