uh........i didn refuse dat da force is constant but m just askin u da reason behind da fallacy
n tell me if U is max y doesn it imply dat da force is zero.......i thin mathematicalyy itz correct 2 say dat ven U is max. dU/dy is zero........the topmost point acts as a maxima for da potential energy curve.
dont u thin so?? n obviously after dat da ball will again start 2 fall .