2. When a force is exerted over an area, we describe the effect
in terms of pressure.
Equation : Pressure=Force/Area
SI Unit of pressure is N/m2 or N/cm2.
Weight is the force produced by gravity acting on a solid,
liquid or gas, pulling the material downwards towards the
centre of the earth.
3. For example:
If a cube has a weight of 500N and an area of 2 m2
Pressure = force/area
500/2
250N/m2
4. Larger the area, lesser the pressure.
Eg- Snow skis have a much larger area than normal
sole of the shoe which helps reduce the pressure on
the snow. Hence, prevents from sinking.
5. STUDS- The tip of studs have a very small area so the
pressure exerted is more. Sports boots have studs on
their soles to prevent slipping and for having more
grip.
Pins- The tip of pin is having a small area so the
pressure exerted is more.
Spikes- Again the tip has small area, increasing the
pressure to be exerted.
Knives-The edge of a sharp knife blade has a very small
area hence it increases the pressure, easily cutting the
objects.
6. Forces that are applied at one point are transmitted to
another point by means of an incompressible fluid.
The pressure is applied to one place and released in
other place.
Eg-1) A car may be raised with a small force by using a
hydraulic jack.
2) The brake system in cars are also hydraulic
mechanism.
7. The middle part of ear is normally filled with air at the
same pressure as the air outside.
The difference in air pressure in and out of the body
causes the ear drum to push outwards. When you
swallow, the air pressure in your middle ear reaches
the same pressure as the air in your throat and outside,
and the eardrum moves quickly back and ear popping
takes place.
