A solid sphere of uniform density and mass M has radius 4 m. Its centre is at the origin of the coordinate system. Two spheres of radii 1 m are taken out so that their centres are P (0, -2,0) and Q (0,2,0) respectively as shown in fig This leaves two spherical cavities.
What is the gravitational field at the origin of the coordinate axis ?
Let p be the density of sphere, R radius of the sphere and r, radius of spherical cavities
Mass of complete sphere
Mass of sphere removed
Here
Now ,