Introduction to fluid mechanics & fluid

• Fluid Mechanics is a branch of science which involve study of behavior of fluid at rest or in motion. This branch of engineering deals with the static, dynamic and kinematic aspects of fluid.
• Fluid statics: It is the study of  fluid when it is at rest.
• e.g.- still water in a tank or a dam. 
• Fluid dynamics: It is the study of behavior of fluid when fluid is in motion, considering all the pressure forces involved during the motion of fluid.
• Fluid kinematics: It is the study of behavior of fluid, when fluid is in motion, ignoring or without considering the pressure forces involved during the flow of fluid.

• What is fluid?
• As the name suggests, in general we can term a material as fluid if it is capable of flowing.
• fluid is a substance having fluidity (ability to flow)  (or)
•  Any substance or material which deforms continuously when subjected to an external shearing force is termed as fluid.
• Examples: All gases and liquids are the examples of fluid (including water vapors/steam)