Question

a block of wood of density 0.8 g/cm³ has a volume of 60 cm³ determine the mass of the block
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Answer 1

Density

$Density = \frac{mass}{vol.} \\ = > 0.8 = \frac{x}{60} \\ = > x = 48kg$

Answer 2

According to Archimedes' principle.

Mass of volume displaced is by object is buoyancy force.

Let the volume of wood is V.

then the volume submerged in liquid is V/4

let the density of wood be ρ.

let the density of liquid be ρ l=0.8cm −3

weight of wood ρVg.

buoyancy force = plV/4 g

now weight of block is equal to buoyancy force.

pVg= plV/4 g

so=p=0.8/4=.2gcm

then the volume submerged in oil is 60% of is 3V/5

weight of wood ρVg

buoyancy force = poil3V/5 g

now weight of block is equal to buoyancy force.

ρVg= poil3V/g

so piol=

$\frac{p \times 5}{3 } = \frac{0.2 \times 5}{3} = 0.33g {cm}^{3}$

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