ABSTRACT

This chapter talks about the basic properties of incompressible fluids that is liquids, and includes a consideration of the pressure due to depth of immersion in a fluid, the thrust exerted on surfaces immersed in them and the energy changes involved in the flow of such fluids. The simple hydrometer is used for the measurement of the density of liquids. The hydrometer is floated in a liquid and the depth to which it floats is a measure of the density of the liquid as it sinks to a level at which the upthrust equals the weights of the hydrometer. If the surface is subject to fluid pressure on both sides then the resultant thrust will be the difference between the two thrusts. Thus there is an upthrust acting on an immersed object equal to the weight of fluid it displaces. This is known as Archimede's Principle and applies to all objects immersed in fluids, regardless of their shape.