A rod of mass `M` and length `L` lying horizontally is free to rotate about a vertical axis through its end. A horizontal force `F` on the rod at the other end, the force always remains perpendicular to the rod. Find the angular velocity of the rod when it has turned an angle `pi//2`.

Explanation

`tau_(o)=FL=I_(0)alpha=(ML^(2))/(3)alpha`
Angular acceleration `alpha=(3F)/(ML)` (constant)
`omega^(2)=omega_(0)^(2)+2alpha theta`
`=0+2xx(3F)/(ML)xx(pi)/(2)`
`omega=sqrt((3piF)/(ML))`