Mechanical Properties Of Fluid

When a rigid object is submerged in a fluid (completely or partially), there exists an upward force on the object that is equal to the weight of the fluid displaced by the object. Buoyant force actual weight weight in water

The dam of water reservoir is made thick at the bottom because due to maximum depth, the pressure of water is maximum and to bear this maximum pressure dam should be thick at the bottom,

According to Bernoulli's theorem, in case of steady flow of incompressible and non-viscous liquid through a tube of non-uniform cross-section, the sum of the pressure, the potential energy per unit volume and the kinetic energy per unit volume is same at every point in the tube, i.e., constant Dividing this expression by , we have constant In this expression is called the 'pressure head', the 'velocity head' and the 'gravitational head'.

Let r be the radius of the each drop. The terminal velocity of drop will be given by ....(i) where is density of drop and a is density of viscous medium of coefficient of viscosity . When two drops each of radius coalesce to form a new drop, then the radius of coalesced drop will be Hence, new terminal velocity of coalesced drop will be ....(ii) From Eqs. (i) and (ii), we get or

An oil. when used as lubricant in a machine, forms a thin layer of the oil over the metallic parts of the machinery. During working of the machinery, the metallic parts do not come in direct contact with each other. The friction between solid-solid surfaces gets converted into friction between solid liquid surfaces. So that the oil layer is effective as lubricant for a long time. The oil should be of high viscosity.