Question

an object floats on water with 20% of its volume above the water time . what is the density of object ? given density of water = 1000kg/m 3

Answer 1

Let V be the volume of the object, d1 be the density of object and d2 be the density of water. Also g signifies acceleration due to gravity. Also we know that 80% of the body is below water.

80% of V is (4V/5)

By Archimedes Law we know that

V×(d1)×g = (4V/5)×(d2)×g

d1 = (4×d2)/5

d1 = (4×1000)/5

d1 = 800 kg/m 3

Answer 2

if 20% is above the surface then 80% is below the surface
% of volume below the surface =density of the object /density of water ×100
80×1000/100=density of the object
800kg/m^3=density of the object