
A shell of mass M and radius R has a point mass m placed at a distance r from its centre. The graph of its gravitational potential energy U(r) vs r will be as shown in figure.





Important Questions on Gravitation


Consider two solid spheres of radii , and masses and respectively. The gravitational field due to sphere and are shown. The value of is:












A spherically symmetric gravitational system of particles has mass density where, is a constant. A test mass can undergo circular motion under the influence of the gravitational field of particles. Its speed as a function of distance from the centre of the system is represented by





From a solid sphere of mass and radius a spherical portion of radius is removed as shown in the figure. Taking gravitational potential at the potential at the centre of the cavity thus formed is (gravitational constant)

