Posted by navneet on .
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

maths 
karuppaiah,
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