(a) What is the mass of a deep breath of air having a volume of $2.00L$? (b) Discuss the effect taking such a breath has on your body’s volume and density.

Fluid statics, often known as hydrostatics, is a branch of fluid mechanics that investigates the state of balance of a floating and submerged body, as well as the pressure in a fluid, or imposed by a fluid, on an immersed body.

The density of a material is defined as the ratio of its mass to its volume.

The density of deep air is usually calculated to be $\rho =1.29\times {10}^{-3}g/mL$

The volume of the deep air is$V=2L$

As we known that the density is the rate of mass per volume let’s put the given data in the formula given below.

$$\begin{gathered} \rho =\frac{m}{V} \\ m=\rho \times V \\ =1.29\times {10}^{-3}\times 2000 \\ =2.58 \text{g} \end{gathered}$$

Therefore, the mass of the deep air is:$\text{2.58 g}$

When you take in more air, your body's volume expands, but your total density decreases. What is the reason behind this?

Because air has a lower density than your body. The average composition of the body's density, such as bone, tissue, and skin, all have various densities. However, the average density of the body is always higher than that of the air.

Therefore, taking a deep breath lowers the total density and increases the volume.