Find the torque of forces about `O`
(`a`)
(`b`)

Explanation

`tau_(o)=2F(d)/(2)+5Fcos37^(@)xx(d)/(2)+5Fsin37^(@)xx(d)/(2)-F(d)/(2)`
`=Fd+5Fxx(4)/(5)xx(d)/(2)+5Fxx(3)/(5)xx(d)/(2)-F(d)/(2)`
`=Fd+2Fd+(3Fd)/(2)-(Fd)/(2)`
`=4 Fd`
(b)
`F_(0)` and `5F_(0) cos 37^(@)` are passing through `O` produces no torque.
`tau_(o)=F_(0)r-5F_(0)sin37^(@)r+10F_(0)r`
`=F_(0)r-5F_(0)xx(3)/(5)r+10F_(0)r`
`=8F_(0)r`