A small submarine, with a hatch door 30 in in diameter, is...

A small submarine, with a hatch door 30 in in diameter, is submerged in seawater. ( $a$ ) If the water hydrostatic force on the hatch is 69,000 lbf, how deep is the sub?
$(b)$ If the sub is $350 \mathrm{ft}$ deep, what is the hydrostatic force
on the hatch?

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Force on a Submerged Surface

The hydrostatic force on a submerged surface is determined by integrating the varying pressure over the area of that surface. For surfaces with uniform pressure distribution or constant geometry, this becomes the product of the pressure at the centroid of the surface and the area of the surface. This concept is central when analyzing structures submerged in fluids, such as submarine hatches.

Fluid Density and Unit Conversions

Understanding the density of the fluid, especially in the context of seawater, is crucial because density directly influences the pressure calculation. Additionally, accurate unit conversions are essential when dealing with different measurement systems (such as inches, feet, and pounds-force) to ensure consistency across calculations in hydrostatics.

Hydrostatic Pressure

Hydrostatic pressure is the pressure exerted by a fluid at rest due to the weight of the fluid above. It increases linearly with depth according to the relation P = ?gh, where ? is the density of the fluid, g is the acceleration due to gravity, and h is the depth below the free surface. This concept is fundamental for evaluating how pressure builds up as a function of depth in any fluid system.

Please give Ace some feedback