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.
- A force, which changes the configuration of a body, is called a deforming force.
- Steel is more elastic than rubber.
Pressure is defined as force acting normally on a unit area of the surface
Pressure = Force/Area
Its unit is N/m2. It is a scalar quantity.
- Atmospheric pressure is measured by an instrument called the barometer.
- Sudden fall in barometric reading is the indication of strom.
- Slow fall in barometric reading is the indication of rain.
- Slow rise in the barometric reading is indication of clear weather.
- The pressure exerted by liquid column at the surface given as p=hdg. Where d is the density of liquid and h is height of liquid column. In a static liquid at same horizontal level, pressure is same at all points.
Atmospheric pressure decreases with altitude that is why
- It is difficult to cook on the mountain.
- The fountain pen of a passenger leaks in aeroplane.
- Bleeding occurs from the ose.
- It is difficult to breath on higher altitude due to less amount partial pressure of oxygen in air.
- Water starts to boil below 100o