Does atmospheric pressure add to the gas pressure in a rigid tank? In a toy balloon? When, in general, does atmospheric pressure not affect the total pressure in a fluid?

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

A rigid body is the body which do not change its shape or structure under the influence of any external force.The distance between the particles of the body remains constant if the body is a rigid body.

A flexible body the distance between the particle is change with the time change.

The ambient pressure does not add to the gas pressure in a rigid tank because the rigid tank can withstand some pressure, ambient pressure does not add to the gas pressure in a rigid tank.

In a toy balloonbecause a toy balloon is not stiff, the pressure within the balloons is equal to air pressure. When the outside air pressure compresses the balloon, the pressure is transferred to the interior gas. If the fluid is contained in a rigid container, atmospheric pressure has no effect.

The gas pressure in a hard tank is unaffected by atmospheric pressure, while the pressure inside a balloon is.

Unless the fluid is contained in a rigid container, ambient pressure impacts fluid pressure.

Therefore,the pressure inside the balloon is affected by atmospheric pressure, but not the pressure inside the rigid tank. If a tank is rigid enough, atmospheric pressure has little effect on the pressure of a fluid.