Force on Sphere Due to Point Charge
The force on the hollow grounded spherical shell due to the presence of the point charge q can be determined by analyzing the electric field created by the point charge inside the shell.

Electric Field Inside the Shell
Since the spherical shell is grounded, the electric potential inside the shell is zero. This means that the electric field inside the shell is also zero. Therefore, the point charge q inside the shell does not create any electric field inside the shell.

Force on the Sphere
Since there is no electric field inside the shell due to the point charge q, there is no force acting on the shell directly from the point charge. However, the charge induces an equal and opposite charge on the inner surface of the shell due to electrostatic induction.
This induced charge on the inner surface of the shell creates an electric field inside the shell that exerts a force on the shell. This force is equal to the force that would be exerted on the induced charge if it were free to move.
The net force on the shell due to the presence of the point charge q is therefore the force exerted by the induced charge on the inner surface of the shell.
In conclusion, the force on the hollow grounded spherical shell due to the presence of the point charge q is the force exerted by the induced charge on the inner surface of the shell, which is equal in magnitude but opposite in direction to the force that would be exerted on the induced charge if it were free to move.