In physics, pressure is that aspect of quantity applied to help one understand how forces come into contact with surfaces. In short, pressure is the measure of the quantity of force applied to some area. It is an important aspect in several physical phenomena and practical applications.
The magnitude of force per unit area on a surface with which it is in contact is said to be the pressure of that force. It tells how much a force is concentrated over an area.
The formula for pressure is given as:
Pressure(P)=Force(F)Area(A)
Where,
F = Force exerted from the body in Newton (N)
A = Total surface area of the object in square meters (m2)
P = Pressure which is always calculated in Pascals (Pa).
Hydrostatic pressure is the normal pressure a fluid asserts when it is stationary, because of the force of gravity. This is the pressure of a fluid at some point within itself in a given depth; that means, it is an important concept in the study of fluid mechanics.
The formula to calculate hydrostatic pressure is:
P=gh
where,
= density
g = gravity
h = height
Problem 1: A girl weighing 60 kg wearing high-heeled shoes balances herself on a single heel. The heel is round with a diameter of 1.5cm. Find the pressure applied by the heel on the horizontal floor.
Answer:
Given: Mass, m = 60kg
Pressure if given by,
Pressure(P)=Force(F)Area(A)
Force, F= mg & Area, A=r2
Hence, P = mg/πr2
Problem 2: A tank filled with water is up to 1m in height. Find how much pressure is exerted on the bottom of the tank.
(Acceleration due to Gravity = 9.8 m/s2, Density of water = 1000 kg / m3).
Solution:
Given: Acceleration due to Gravity = 9.8 m/s2
Density of water = 1000 kg / m3,
The pressure is expressed as
P = ρ × g × h
P = 1000 × 9.8 × 1m
P = 9800 Pascal.
The pressure is the ratio of force applied to anything, over an area. It is a pretty general concept in general terms and has formed the basis of scientific and practical applications as varied as fluid dynamics to structural engineering.
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