A circular ring has radius r and mass M. Let L label the axis of the ring (the line that is perpendicular to the plane of the ring and that passes through the center of the ring). What is the force on a mass m that is located on L, at a distance x from the center of the ring? A hole with radius R is cut out from an infinite flat sheet with mass density (kg/m2). What is the force on a mass m that is located on the analogously defined line L, at a distance x from the center of the hole? Hint: Consider the plane to consist of many concentric rings, and integrate over the rings