Ch 4 - Pressure and Fluids and Atmospheric Pressure

Thurst

When a force is applied in a direction perpendicular to the surface.

Pressure

The effect of thrust on a surface depends on the area of the surface on which it acts.

Fluids

A substance which can flow.

S.I. Unit of Thrust

Newton

S.I. Unit of Pressure

Pascal

Laws of Liquid Pressure

1. Inside the liquid pressure increases with the increase in depth from its free surface.

2. In a stationary liquid pressure is same at all points on a horizontal plane.

3. Pressure is same and all directions about a point inside the liquid.

4. Pressure at same depth is different in different liquids it increases with the increase in density of liquid.

5. A liquid seeks own level.

Principal of Hydraulic Machines

A small force applied on a smaller piston is transmitted to produce a large force on the bigger piston.