Question

A piece of wood having 80cc volume when floated on water remain 60cc volume above the water then relative density is

Answer 1

the relative density is 0.25

Explanation :

since the wood floats on water , it's weight must be equal to the upthrust

volume of the wood inside water = 80 - 60 = 20 cc

Hence the upthrust will be equal to weight of 20 cc water

so we have

W = U

=> ρVg = ρ₁v₁g

where

ρ = density of wood

V = volume of wood = 80 cc

g = accel. due to gravity

ρ₁ = density of water

v₁ = volume of water displaced = 20 cc

we know that relative density = ρ/ρ₁

putting these values we get,

(ρ/ρ₁) = v₁/V = 20/80 = 0.25

Hence the relative density is 0.25