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

Answer

A

Explanation

If the perpendicular distance of any side of the triangle from `O` is `x` then `F_(1)x+F_(2)x-F_(3)x=0`
`rArrF_(1)+F_(2)=F_(3)`