Find the total torque acting on the body shown in the figure about the point `O`.

Explanation

To determine torque, sometimes we break force into components or in some situations, we break distance from line of action of force into components in such a manner that force and distance are perpendicular.

`tau_(o)=-Fr+Fxx0+Fxxr sin30^(@)+Fsin30^(@)xxr`
`=-Fr+(Fr)/(2)+(Fr)/(2)=0`