`O` is the centre of an equilateral triangle `ABC`. `F_(1), F_(2)` and `F_(3)` are the three forces acting along the sides `AB, BC` and `AC` respectively. What should be the value of `F_(3)` so that the total torque about `O` is zero?

Options

A. `((F_(1)+F_(2)))/(2)`
B. `(F_(1)-F_(2))`
C. `(F_(1)+F_(2))`
D. `2(F_(1)+F_(2))`

Answer

C

Explanation

For total torque about O to be zero

`F_(1)^(r)+F_(2^(r))-F_(3^(r))=0rArr phi_(3)=phi_(1)+phi_(2)rArr F_(3)=F_(1)+F_(2)`