Chapter 2: The Pressure

Topics Covered:

• Effects of Pressure
• Formula of Pressure
• Hydrostatic Pressure
• Pascal's Law
• Relative Density
• Archimedes' Principle
• Principle of Floatation
• Atmospheric Pressure
• Application of Pressure

Pressure and Its Principles

What is Pressure?

• Pressure: Force/Surface Area
• Directly proportional to the force applied
• Inversely proportional to the surface area

Hydrostatic Pressure

• When a liquid is poured into a container, the pressure is exerted at the bottom of the container.
• Formula:
  • Pressure (P) = Force (F) / Area (A)
  • F = mg (force's mass weight)
  • V (Volume) = A * h (surface area * height)
• Formula for Liquid Pressure:
  • P = h * ρ * g (h - height, ρ - density, g - gravitational acceleration)

Pascal's Law

• When a liquid confined in a container is compressed at any point, the pressure is uniformly distributed.
• Example: Hydraulic Press
  • f1/a1 = f2/a2 (pressure is the same from the smaller opening to the larger opening)

Archimedes' Principle

• Balance of pressure displacement and weight
• Example: Rectangular body and applying pressure with its surface area
• Weight of displaced liquid is equal to the applied pressure

Relative Density

• Density: Mass/Volume (ρ = m/V)
• Relative Density: Comparison of the density of a substance with that of water

Atmospheric Pressure

• Gaseous Pressure: Effects of gas and correct measurement
• ATM pressure at sea level: 1.013 x 10^5 Pascals
• Relationship between height and ATM pressure

Application of Pressure

• Water Pumps
• Use of pressure in various devices