Question

Radius of iron sphere is 0.21 cm. The density of iron is 7.8g/cm find mass

Answer 1

volume of sphere = 4/3 pi r^3
= 4/3 x 22/7 x (21/100)^3 = 0.09 cm^3

mass = volume x density
=0.09 x 7.8 = 0.7 g