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printed 56 · PDF 56
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Topic 1.8: Pressure
What is pressure?
Pressure is defined as the force per unit area acting on a surface.
It is measured in Pascals(Pa).
The equation for pressure is P=F/A, where P=pressure, F=Force and
A=area.
Pressure is inversely proportional to area which means that if area in
contact with the surface is reduced then pressure will increase.
Pressure is directly proportional to Force which means more the force
applied on an object more the pressure it exerts.
Eg: a knife is sharpened so that fruits are easily sliced. It is sharpened to
reduce its area in contact with the surface of fruit and with the same force
applied, fruit is easily sliced.
Atmospheric pressure is approximately 100,000Pa
To determine pressure on an object placed in liquid the formula is Pressure
in liquids= ρgh where “ρ” is density of the liquid “g” is gravity and “h” is
height or distance between surface of liquid and object (depth)
We can see by the formula that width of any container has no effect on
pressure.