A force `vecF=Ahati+Bhatj` is applied to a point whose radius vector relative to the origin is `vecr=ahati+bhatj`, where `a`, `b`, `A`,`B` are constants and `hati`, `hatj` are unit vectors along the `X` and `Y` axes. Find the torque `vectau` and the arm `l` of the force `vecF` relative to the point `O`.

Explanation

`vectau=vecrxxvecF=|[hati,hatj,hatk],[a,b,0],[A,B,0]|`
`vectau=(aB-bA)hatk`
Lever arm `l= (|vectau|)/(|vecF)|=((aB-bA))/(sqrt(A^(2)+B^(2)))`
`{{:(tau=rFsintheta implies r sintheta=(tau)/(F)),(r sin theta:"lever arm"):}}`