Physics: Types of Forces and Pressure in Fluids

Types of Forces

• Contact Forces: Forces that act through physical contact between objects, e.g.:
  • Frictional force
  • Normal force
  • Tension force
  • Air resistance force
• Non-Contact Forces: Forces that act without physical contact between objects, e.g.:
  • Gravitational force
  • Electromagnetic force
  • Magnetic force

Pressure in Fluids

• Pressure: Force per unit area, measured in Pascals (Pa) or pounds per square inch (psi)
• Fluid Pressure: Pressure exerted by a fluid (liquid or gas) on an object, e.g.:
  • Hydrostatic pressure in a liquid
  • Air pressure in a gas
• Pascal's Principle: Pressure applied to a confined fluid is transmitted equally in all directions and to the walls of the container

Atmospheric Pressure

• Atmospheric Pressure: Pressure exerted by the weight of the atmosphere on the Earth's surface, approximately 1013 mbar or 1 atm
• Factors Affecting Atmospheric Pressure:
  • Altitude: Decreases with increasing altitude
  • Weather: Changes with weather patterns, e.g. high pressure in clear weather, low pressure in storms
  • Temperature: Increases with increasing temperature
• Measurement of Atmospheric Pressure: Using barometers, e.g.:
  • Mercury barometer
  • Aneroid barometer
  • Digital barometer

Types of Forces

• Contact forces act through physical contact between objects and include frictional force, normal force, tension force, and air resistance force
• Non-contact forces act without physical contact between objects and include gravitational force, electromagnetic force, and magnetic force

Pressure in Fluids

Definition of Pressure

• Pressure is force per unit area, measured in Pascals (Pa) or pounds per square inch (psi)

Fluid Pressure

• Fluid pressure is the pressure exerted by a fluid (liquid or gas) on an object
• Examples of fluid pressure include hydrostatic pressure in a liquid and air pressure in a gas

Pascal's Principle

• Pressure applied to a confined fluid is transmitted equally in all directions and to the walls of the container

Atmospheric Pressure

Definition of Atmospheric Pressure

• Atmospheric pressure is the pressure exerted by the weight of the atmosphere on the Earth's surface

Facts About Atmospheric Pressure

• Atmospheric pressure is approximately 1013 mbar or 1 atm
• Atmospheric pressure decreases with increasing altitude
• Atmospheric pressure changes with weather patterns (high pressure in clear weather, low pressure in storms)
• Atmospheric pressure increases with increasing temperature

Measurement of Atmospheric Pressure

• Atmospheric pressure can be measured using barometers
• Types of barometers include:
  • Mercury barometer
  • Aneroid barometer
  • Digital barometer