Q.
$ABC$ is an equilateral triangle with $O$ as its centre. ${\overrightarrow{F}}_{1},\ {\overrightarrow{F}}_{2}$ and ${\overrightarrow{F}}_{3}$ represent three forces acting along the sides $AB,\ BC$ and $AC$ respectively. If the total torque about $O$ is zero then the magnitude of ${\overrightarrow{F}}_{3}$ is
A) $F_{1} + F_{2}$
B) $F_{1} - F_{2}$
C) $\frac{F_{1} + F_{2}}{2}$
D) $2(F_{1} + F_{2})$
Explanation
(a) $F_{1}x + F_{2}x = F_{3}x$
$F_{3} = F_{1} + F_{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.