Heroes in movies hide beneath water and breathe through a hollow reed (villains never catch on to this trick). In practice, you cannot inhale in this manner if your lungs are more than\[{\rm{60}}{\rm{.0 cm}}\]below the surface. What is the maximum negative gauge pressure you can create in your lungs on dry land, assuming you can achieve −\[{\rm{3}}{\rm{.00 cm}}\]water pressure with your lungs\[{\rm{60}}{\rm{.0 cm}}\]below the surface?

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 force per unit perpendicular area across which the force is exerted is known as pressure. Pressure is defined as follows in equation form:

\[P = \frac{F}{A}\]

The pressure inside the chest should be always less than the atmospheric pressure than only we can breathe.

The negative side means less amount of pressure than other surface.

Pressure at bottom =Pressure in air + pressure due to column of water.

Step 3: Pressure in dry land

By putting all the value into the equation, we get:

\begin{aligned}{P_b} &= {P_a} + {P_w}\\ - 3\,{\rm{cm}}\;\,{\rm{of}}\;\,{{\rm{H}}_{\rm{2}}}{\rm{O}} &= {P_a}+60\,{\rm{cm}}\;\,{\rm{of}}\;\,{{\rm{H}}_{\rm{2}}}{\rm{O}}\\{P_a} &=- 63\,\,{\rm{cm}}\;\,{\rm{of}}\;\,{{\rm{H}}_{\rm{2}}}{\rm{O}}\end{aligned}

Therefore, pressure inside the lungs is \[{\rm{ - 63 cm}}\] of water.