Question

A solid sphere of radius 4cm has a mass of 64kg.what will be the mass of a shell of the same metal whose internal and external radii are 2cm and 3cm respectively?Show working

Answer 1

The 2cm sphere has 8/64 the volume of the 4cm sphere

The 3cm sphere has 27/64 the volume of the 4cm sphere
So the mass of the shell will be 27-8 = 19 kg