Question

A sphere of radius 4 cm iss carved from a homogenous sphere of radius 8cm and mass 160g. the mass of the smaller sphere is

Answer 1

Since the material is same, the density is also same. The formula for mass of the sphere m =Volume x density
=4/3 (pi) (r)^3 x density
m1= 160g, r1=8cm.
r2=4cm, m2=?
160=4/3 (pi) (8)^3x density-----(1)
m2=4/3 (pi) (4)^3x density-----(2)
now equation (2)/(1)
m2/160= (4)^3/(8)^3
m2=(4/8)^3 x 160
=160/8
=20 gm
simple formula is
m2=(r2/r1)^3 x m1

Answer 2

m2=(4/8)^3*160
=20g