BME Application $1$: An atomic force microscope $($AFM$)$ is a state$-$of$-$the$-$art device used to study the

mechanical and topological properties of surfaces on length scales as small as atoms. The device uses a flexible

cantilever beam with a stiff tip that is brought into contact with the surface to be studied. Due to the contact

forces at the tip $($ C in the diagram below$),$ the beam deflects and induces resultant forces and a resultant

moment at A$.$ The AFM is finely calibrated to convert reaction forces and moment to mechanical and

topological properties of surfaces. Based on the forces and lengths in the figure, what is the resultant moment

at A$?$