Question

A piece of wood of uniform cross-section and 16 cm height sinks 10 cm in water and 12 cm in spirit. Find the relative densities of wood and spirit.

Answer 1

Let densities of water, wood and spirit are ρ, ρw and ρs respectively.

Let A be the area of the wooden block.

Total volume of the wooden block is, V = 15A

1. Mass of wood = Mass of water displaced by the wood

Vρwg = A×10×ρ×g



2. Mass of the wood = Mass of then spirit displaced

Vρwg = A×12×ρs×g

ρs = 0.83 g/cm3