Question

a ball weighing 4 kg of density 4000 kg/ m³ is completely immersed in water of density 10³ kg / m³.what is the force of buoyancy on it ( 10m/s²)

calculate the no. of molecules in 56g of nitrogen

If the relative density of mercury is 13.6. what's its density in si unitt

Answer 1

Given:

Volume of the ball immersed = 4/4000 = 0.001 m³ and density of water, d = 10³ kg / m³.

(1)Suppose a body of volume ‘V’ is immersed in a fluid of density ‘d’. Since, it is immersed fully the volume of fluid displaced is also equal to V. Then

The buoyant force on the body is, F_B = Vdg, ‘g’ is acceleration due to gravity.

Substitute the values we can get the desired answer.
(2) Given mass = 56 g

Number of atoms can be calculated by using:

• Number of atoms = Moles * Avogadro's number

Number of moles = Given mass / molar mass

(3) If the relative density of mercury is 13.6

The relative density of a substance is the ratio of its density to that of water .

Relative density = Density of a substance / Density of water

So here in this case, Density of a mercury = 13.6 (Density of water)