Effect of change in area ; class 8
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Transcript of Effect of change in area ; class 8
EFFECT OF CHANGE IN
AREA ON PRESSURE OF A GIVEN FORCE IN
OUR DAY TO DAY LIFE
Submited by:Rahul Mohanty
Rasseswari SarangiPriyanka sahoo
Rasseswari SarangiRimisha Parida
PASCAL’S LAW “The pressure exerted anywhere in an
enclosed incompressible and non-viscous fluid is transmitted equally and undiminished in all directions through out the fluid, provided the effect of gravity is neglected”
P=F/A The equation shows that pressure is
inversely proportional to area.
EXAMPLES FOUNDATION OF BUILDINGS The foundation off building is made more broader than the rest of the
building so that the pressure exerted by the weight on earth can be decreased.
SHOULDER STRAPS OF SCHOOL BAGS The shoulder straps of school bags are made wider and soft so that the
pressure exerted by the heavy bags on shoulders can be reduced. You can feel the paining pressure if you try to replace the broad strap with a narrow one.
MILITARY TANK The Military tanks have a broad chain so that the pressure exerted by
the heavy vehicle on ground is a minimum and it can travel even through marshy places
HEAVY VEHICLES HAVE MORE TYRES When vehicles get struck in marshy places, wooden planks are used
for the vehicle to come up.
WHY THE RAILWAY TRACK ARE LAID ON LARGE SIZED WOODEN OR IRON SLEEPERS? Trains have huge masses and rails are
narrow. Therefore if they are directly put on earth, they will sink down due to the extreme pressure it would exert on earth when run over by the train. So they are laid on wooden or iron sleepers of large area so that pressure on earth is reduced.
Pressure = Force /Area. As area increases pressure decreases.
PRESSURE MEASUREMENT
A manometer is an instrument that uses a column of liquid to measure pressure.
A vacuum gauge is used to measure the pressure in a vacuum.
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure.
MORE EQUATIONS!!!
Liquid Pressure = ρgh where….. ρ = mass/volume
= fluid density g = acceleration of gravity
h =height or depth of fluid
THRUST:Thrust is defined as the force acting normal to a surface. Pressure is the thrust acting per unit area. CUTTING TOOLS Cutting tools have sharp edges with very
low area so that high pressure can be applied by a small force. You can realise this if you try to cut a tomato with a blunt knife and try again after sharpening it.
NAILS AND DRAWING PINS Nails and pins have sharp ends so that it
can pierce into wooden boards and walls easily by applying a small force.
EQUATIONS FOR PRESSURE Pressure = Force/surface area Pressure = Newtons (Kg x m/s/s) side x side Units are in Pascals or N/m²
The whole system is a low pressure, but it dramatically decreases towards the eye of the hurricane
Pressure always flows from high to low, which creates the high velocity winds.