Answer:
m = 4.5021 kg
Explanation:
given,
Apparent mass of aluminium = 4.5 kg
density of air = 1.29 kg/m³
density of aluminium = 2.7 x 10⁷ kg/m³
true mass of the aluminium = ?
Weight in Vacuum
W = m g
W = ρV g
Air buoyancy acting on aluminium
B = ρ₀V g
Volume is the same in both cases since the volume of the aluminum
displaces an equal amount of volume air.
Apparent weight:
ρV g − ρ₀V g = 4.5 g
ρV − ρ₀V = 4.5
[tex]V = \dfrac{4.5}{\rho - \rho_0}[/tex]
m = ρV
[tex]m = \dfrac{4.5\times \rho}{\rho - \rho_0}[/tex]
[tex]m = \dfrac{4.5\times 2700}{2700 - 1.29}[/tex]
m = 4.5021 kg