Question

Write a few lines about: Fluids, Density, Pressure, change of Pressure with Depth in a liquid (water) and Archimedes’ Principle. What the SI units on each of them and give some practical example of each of them.

Answer 1

A fluid is any substance that flows or deforms under an applied shear stress.The have zero resistance to tangential stress.They possess any shape of vessel in which its kept.Fluid,is any liquid or gas or generally any material that cannot sustain a tangential, or shearing, force when at rest and that undergoes a continuous change in shape when subjected to such a stress. This continuous and irrecoverable change of position of one part of the material relative to another part when under shear stress constitutes flow, a characteristic property of fluids.

for example Water, Gas

Density is a characteristic property of a substance.The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume).The mass of atoms, their size, and how they are arranged determine the density of a substance.

Density equals the mass of the substance divided by its volume; D = m/v.

S I unit is

Archimedes’ Principle   physical law of buoyancy, discovered by the ancient Greek mathematician and inventor Archimedes, stating that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body. The volume of displaced fluid is equivalent to the volume of an object fully immersed in a fluid or to that fraction of the volume below the surface for an object partially submerged in a liquid. The weight of the displaced portion of the fluid is equivalent to the magnitude of the buoyant force. The buoyant force on a body floating in a liquid or gas is also equivalent in magnitude to the weight of the floating object and is opposite in direction; the object neither rises nor sinks. For example, a ship that is launched sinks into the ocean until the weight of the water it displaces is just equal to its own weight. As the ship is loaded, it sinks deeper, displacing more water, and so the magnitude of the buoyant force continuously matches the weight of the ship and its cargo.

Pressure exerted by a static fluid depends only upon the depth of the fluid, the density of the fluid, and the acceleration of gravity.The pressure in a static fluid arises from the weight of the fluid.It is given by