A rubber ball floats on water with it’s 1/3^rd volume outside water. What is the density of rubber ?

V = total volume of rubber ball

ρ = density of the rubber ball

1/3^rd of V is outside water

Therefore, volume inside water V – 1\over3V = 2\over3V

By the principle of flotation,

Weight of ball = Weight of water displaced by the immersed part of the ball.

and density of water = 1000 kg m^-3

i.e., V × ρ × g = 2\over3V × 1000 × g

Hence, ρ = 2000/3 = 667 kg m^-3

Hence,

Density of rubber = 667 kg m^-3