`tau_(o)=Fcosphi l=I_(0)alpha=(ml^(2))/(3)alpha`
`alpha=(3Fcosphi)/(ml)` (variable angular acceleration)
`omega(domega)/(dphi)=(3Fcosphi)/(ml)`
`int_(0)^(omega)omega domega=(3F)/(ml)int_(0)^(omega)cosphidphi`
`(omega^(2))/(2)=(3F)/(ml)sinphi implies sqrt((6fsinphi)/(ml))`