# Pressure: Liquid Pressure, Pascal's Law and Upthrust ﻿ ﻿Liquid Pressure

﻿Liquid pressure is the increase in pressure at increasing depths in a liquid. This pressure increases because the liquid at lower depths also has to support water all above it. We calculate liquid pressure using the equation Liquid Pressure=mass*acceleration due to gravity*depth in liquid. To further prove this formulae,             Here is a link for the video: https://www.brightstorm.com/science/physics/solids-liquids-and-gases/liquid-pressure/?jwsource=cl

we know, pressure is the force applied on unit area

Hence, P= F/A

or, P=  m*g/A           [since, F= mg]
or, P= d*v*g/A          [since, d= m/v or, m= d*v] or, P= d*A*h*g/A      [since, V= A*h]

Therefore, P=d*h*g   P= liquid pressure

Also, P  ﻿h.

And, pressure is measured in Nm-2 in S.I. system. But liquid pressure is also measured in mm of Hg.

﻿Pascal's Law

﻿Pascal's Law, in fluid mechanics, statement that, in a fluid at rest in a closed container, a pressure change in one part is transmitted without loss to every portion of the fluid and to the walls of the container . The principal was introduced by Blaise Pascal (June 19, 1623 - Aug 19, 1662) .

﻿﻿Applications of Pascal's Law

﻿Now since you may have understood something about pascal's law here are some of it's application and you will know them through some given videos.

﻿Upthrust

﻿It will be explained through points.

• Upthrust is a force which pushes upwards on an object submerged in a fluid.
• Also known as buoyancy force, upthrust is due to the difference is hydrostatic pressure at the top and bottom of the immersed object
• The force of upthrust is significantly larger than in gases, this is because liquids are much denser than gas
• Recall that hydrostatic pressure depends on the height (h) or depth that an object is submerged in from P=d*g*h
• Therefore, the water pressure at the bottom of an object is greater than that at the top of as shown in diagram at the right ﻿