5. {15] An object of mass III is on the surface of a planet with gravity that shrinks exponentially with altitude [y] above the surface given by F = FileWI}, where E] and Y describe the surface gravity strength and rate of decline with altitude respectively. {Just so you know such a force lastr can't exist due to standard gravity in an inertial frame. but let's pretend it can]. Find the expression for gravitational potential energy. and then use Lagrangian mechanics to nd the dynamical equations describing the velocity and height of a ball thrown upward vertically on the surface of such a planet