SSC CGL
Insurance
NABARD
CAPF
RBI Assistant
IBPS PO
SBI PO
Shorts SSC CGL Practice
More Articles
- Pressure
- Unit and Dimension
- Motion in Daily Life
- Work, Energy and Power
- Gravitation
- Floatation
- Surface Tension
- Viscosity
- Elasticity
- Simple Harmonic Motion
- Wave
- Sound Wave
- Heat
- Light
- Static Electricity
- Current Electricity
- Magnetism
- Atomic & Nuclear Physics
- Electronics
- Scientific Instruments & Thier Uses
- Inventions & their Inventors
- Important Discoveries in Physics
- S.I. Units of Physical Quantity
- Conversion of Units from One System to another System
Pressure
Pressure is defined as force acting normally on unit area of the surface.
SI unit of pressure is N/m2 also called pascal (Pa), Pressure is a scalar quantity.
Some application of the concept of pressure:
- The bags and suitcases are provided with broad handles so that small pressure is exerted on the hand while carrying them.
- Railway tracks are laid on large-sized wooden sleepers so that thrust due to weight of train is spread over a large area.
- Pins are made to have pointed ends. This explains why needle is used to brust a gas filled balloon because needle exerts more pressure.
Atmospheric Pressure:
Atmospheric pressure is that is that pressure which is exerted by a mercury column of 76 cm; length at 0°C at 45° latitude at the sea-level. It is equal to weight of 76 cm column of mercury of cross-sectional area 1 cm2. Generally it is measured in bar. 1 bar = 105 N/m2
Atmospheric pressure 1 atm = 1.01 bar = 1.01 x 105 N/ m2= 760 torr
One torr is the pressure exerted by a mercury column of 1 mm length.
- Atmospheric pressure decreases with altitude (height from earth's surface). This is why 1. It is difficult to cook on the mountain 2. The fountain pen of a passenger leaks in aeroplane at height.
- Atmospheric pressure is measured by barometer. With the help of barometer, weather forecast can be made.
- Sudden fall in barometric reading is the indication of storm.
- Slow fall in barometric reading is the indication of rain.
- Slow rise in the barometric reading is the indication of clear weather.
Pressure in liquid:
Force exerted on unit area of wall or base of the container by the molecules of liquid is the pressure of liquid. The pressure exerted by liquid at depth h below the surface of liquid is given as p = hdg where d is the density of liquid.
- Regarding pressure, the following points are worth noting:
1. In a static liquid at same horizontal level, pressure is same at all points.
2. Pressure at a point in a static liquid has same value in ill directions
3. Pressure at a point in a liquid is proportional to the depth of the point from the free surface.
4. Pressure at a point in a liquid is proportional to the density of the liquid.
Pascal law for pressure of liquid
1. If gravitational attraction is negligible, in equilibrium addition, pressure is same at all points in a liquid.
2. If an external pressure is applied to an exclosed fluid, it transmitted undiminished to every direction.
- Hydrolic lift, hydrolic press, Hydrolic brake work on Fiscal law.
More Related Articles
Unit and Dimension Unit: The chosen standard used for measuring a physical quantity is called unit. The unit should be: 1. Well defined 2. Easy to reproduce 3. Easy to compare
by
ExamGuruMotion When an object shifts its position in relation to a reference point within a specific time frame, it is said to be in motion. The change in a body's position with respect to a frame
Work, Energy, and Power Work If a body gets displaced when a force acts on it, work is said to be done. Work is measured by the product of force and displacement of the body al
Gravitation: Every body attracts other body by a force called force of gravitation. Newton's law of Gravitation: The force of gravitational attraction between two point bodies is directly
Buoyant Force: When a body is immersed party or wholly in a liquid, a force acts on the body by the liquid in the upward direction. This force is called Buoyant force or force of buoyancy or upthr
Cohesive Force: The force of attraction between the molecules of same substance is called cohesive force. Cohesive force is maximum in solids. This is why solids have a fixed shape. Cohesive force is
Viscous force: The force which opposes the relative motion between different layers of liquid or gases is called viscous force. Viscosity: Viscosity is the property of a liquid by virtue of
Elasticity: Elasticity is the property of material of a body by virtue of which the body acquires its original shape and size after the removal of deforming force. Elastic Limit: Elastic limi
Periodic Motion: Any motion which repeats itself after regular interval of time is called periodic or harmonic motion. Motion of hands of a clock, motion of earth around the sun, motion of the need
A wave is a disturbance which propagates energy from one place to the other without the transport of matter. Waves are broadly of two types: 1. Mechanical Wave 2. Non-mechanical Wave 1. Me
