Question

5. Calculate the mass of a body whose volume is 3 m^3
and relative density is 0.75.
[Ans. 2250 kg]​

Answer 1

GIVEN :-

• Volume (V) = 3 m³.
• Relative Density (RD) = 0.75.

TO FIND :-

• The mass of The body .

SOLUTION :-

As we know that,

➺ Density of water = 1000 kg/m³.

➺ Relative Density = Density of body/Density of water.

Substitute The given Values,

➺ 0.75 = Density of body/1000 kg/m³.

➺ Density of body = 1000 kg/m³ × 0.75

➺ Density of body = 750 kg/m³.

❏ Hence the Density of object is 750 kg/m³.

As we know that,

➺ Mass of body = Density × Volume

Substitute the Given values,

➺ 750 kg/m³ × 3m³

➺ 2250 kg.

❏ Hence the mass of body is 2250 kg.

Answer 2

Given :-

• Volume = 3m³
• Relative Density = 0.75

To Find :-

• Mass of the body

Solution :-

We know that,

$\tt \to Density \: of \: water = {1000 \: kg/m}^{3}$

$\to \tt Relative \: Density = \frac{Density \: of \: body}{Density \: of \: water}$

Put the values,

$\tt 0.75 = \frac{Density \: of \: body}{{1000 \: kg/m}^{3}} \\ \\ \implies \tt Density \: of \: body = {1000 \: kg/m}^{3} \times 0.75 \\ \\ \implies\tt Density \: of \: body = {750 \:kg/m }^{3}$

★ Hence, the density of the object is 750 kg/m³.

We need to find the mass of the body :-

We know that,

$\tt\to Mass \: of \: body = Density \times Volume$

Put the values,

$\tt {750 \: kg/m}^{3} \times {3m}^{3} \\ \tt= 2250 </strong><strong>\:</strong><strong> </strong><strong>kg$

★ Hence, the mass of the body is 2250 kg.