Page 1 - lesson notes- fluid pressure

SAI INTERNATIONAL SCHOOL
Class8
Lesson Notes
Subject-Physics
CH-Force and Pressure
Subtopic-Fluid pressure

NOTES: Fluid Pressure:
• Definition of Fluid pressure: Fluid pressure is defined as the pressure exerted
by the fluids on the objects immersed in it or on the walls of the container.
• (Liquids and gases are known as fluids)

Properties of Liquid Pressure
• Pressure exerted by Liquid on the base of the container depends on the height of
fluid column.
• Liquid exerts pressure on the walls of the container.
• Liquid exerts equal pressure at the same depth.
• As the depth increases liquid pressure also increase

Factors affecting Liquid Pressure
1. Height of fluid column
2. Density of fluid
3. Acceleration due to gravity
(Fluid pressure= height of Fluid column X density of fluid X acceleration due to gravity
= hdg)

Significance & Applications of liquid pressure
a. The base of a Dam is made broader, to with stand the high fluid pressure at
depth.
b. Deep sea divers wear special kind of body suit to protect them from high fluid
pressure.
c. Deep sea fishes die when brought to the surface of the sea, because the
pressure of their body is adapted to the high pressure of deep sea. On the sea
level the pressure is comparatively lesser than the body pressure of fish as a
result they die.
d. When we inflate a balloon the pressure by the gas is exerted on the inner walls of
the balloon and it inflates.

Characteristics of Fluid Pressure
Increases with Depth: In liquids, pressure increases with depth. The deeper you go,
the greater the pressure.