## FLUID MECHANICS AND FLUID MACHINES:-

**Definition:**

Fluid is a substance which is capable of flowing under the action of shear force ,however small is the shear force.

scope of fluid mechanics:

- designing of ships
- working of pumps,compressors

Classification of fluids:

- Liquids
- Gases

Properties of Fluids:

1**.DENSITY OR MASS DENSITY (ρ):**

- density is defined as the ratio of mass of fluid to its volume
- ρ(rho) =mass of fluid(kg) / Volume of fluid ( m
^{3}) - ρ of water is 1000 kg/m
^{3 } - ρ of mercury is 13600 kg/m
^{3} - Dimentional Analysis = ML
^{-3 } - it is an absolute quantity i.e it does not change from place to place.

^{2. SPECIFIC WEIGHT }^{ (w):}

- specific weight is defined as the ratio of weight per unit volume
- specific weight(w) = weight of fluid (N) / volume of fluid (m
^{3}) - w= ρ * g.
- w of water is 9810 N/m
^{3} - Dimentional Analysis = ML
^{-2 }T^{-2}