Question

A tree trunk (whose wood has a density of 780 kg/m3
) is floating in
a river. What percentage of the wood’s volume stays above water
(density = 1000 kg/m3
)?

Answer 1

Hey Dear,

◆ Answer -

Percentage of floating part of wood = 22% .

◆ Explanation -

Let V be volume of the wood and V0 be that for immersed part.

For the wood to float-

Buoyanct force by immersed part = Weight of wood

d0.V0.g = d.V.g

V0 = d.V/d0

Volume of wood outside water-

V' = V - V0

V' = V - V.d/d0

V' = V (1-d/d0)

Percentagae of floating wood -

V'/V % = V (1-d/d0) / V × 100

V'/V % = (1-780/1000) × 100

V'/V % = 22 %.

Hence, percentage of floating part wood is 22% .

Hope that is helpful...