A wooden block (SG = 0.6) floats in oil (GS = 0.8). What fraction of the volume of the block is submerged in oil?

Respuesta :

Answer:

3/4 th fraction of the volume of block is submerged in oil.

Explanation:

We know that

density of the block, ρ[tex]_{b}[/tex] =SG[tex]\times[/tex]density of water

                                                           = 0.6[tex]\times[/tex] 1000

                                                           = 600 kg/[tex]m^{3}[/tex]

density of the oil, ρ[tex]_{o}[/tex] =SG [tex]\times[/tex] denity of water

                                                           = 0.8[tex]\times[/tex] 1000

                                                           = 800 kg/[tex]m^{3}[/tex]

Let acceleration due to gravity, g = 9.81 m/[tex]s^{2}[/tex]

Volume of block submerged in oil is [tex]V_{1}[/tex]

Volume of block above the oil surface is [tex]V_{2}[/tex]

The total volume of the block is V = [tex]V_{1}[/tex]+[tex]V_{2}[/tex]

Therefore for a partially submerged body, we know that

Buoyant force = total weight of the block

and

total weight of the block = Weight of the fluid displaced by the block

ρ[tex]_{b}[/tex]\timesV\timesg = ρ[tex]_{o}[/tex]\times[tex]V_{1}[/tex]\times g

600([tex]V_{1}[/tex]+[tex]V_{2}[/tex]) = 800 [tex]V_{1}[/tex]

600[tex]V_{1}[/tex] + 600[tex]V_{2}[/tex] = 800 [tex]V_{1}[/tex]

600[tex]V_{2}[/tex] = 800 [tex]V_{1}[/tex] - 600[tex]V_{1}[/tex]

600[tex]V_{2}[/tex] = 200[tex]V_{1}[/tex]

[tex]\frac{V_{1}}{V_{2}}[/tex] = [tex]\frac{600}{200}[/tex]

Thus [tex]V_{1}[/tex] = 600

        [tex]V_{2}[/tex] = 200

        V = 600+200

            = 800

Therefore fraction of volume of the block submerged in oil is,

       [tex]\frac{V_{1}}{V}[/tex] = [tex]\frac{600}{800}[/tex]

       [tex]\frac{V_{1}}{V}[/tex] = [tex]\frac{3}{4}[/tex]