Physics: Types of Forces and Pressure

Study Notes

Pressure: The force exerted per unit area on an object
- Measured in units of pascals (Pa) or pounds per square inch (psi)
- Formula: Pressure (P) = Force (F) / Area (A)
- P = F / A
Area: The size of the surface on which the force is acting
- Measured in units of square meters (m²) or square inches (in²)
Relationship between pressure and area:
- As the area decreases, the pressure increases
- As the area increases, the pressure decreases

Atmospheric Pressure: The pressure exerted by the weight of the air in the atmosphere
- Measured in units of pascals (Pa) or atmospheres (atm)
- Standard atmospheric pressure at sea level: 101,325 Pa or 1 atm
Factors affecting atmospheric pressure:
- Altitude: Atmospheric pressure decreases with increasing altitude
- Weather: Changes in atmospheric pressure are associated with changes in weather patterns
- Temperature: Atmospheric pressure is affected by temperature changes

Contact Forces: Require direct interaction between objects.
- Frictional Force: Resists motion between two surfaces in contact.
- Normal Force: Acts perpendicular to the surface, supporting the weight of an object.
- Tension Force: Exerted by a string, cable, or rope when it is pulled tight.
Non-Contact Forces: Can act at a distance without physical contact.
- Gravitational Force: Pulls objects toward one another, dependent on mass and distance.
- Electromagnetic Force: Acts between charged particles, responsible for electricity and magnetism.
- Magnetic Force: Acts on magnets and magnetic materials, influencing their motion and alignment.

Pressure: Defined as the force applied over a unit area.
- Units: Pascals (Pa) or pounds per square inch (psi).
- Formula: P = F / A, where P is pressure, F is force, and A is area.
Area: Refers to the surface size upon which a force acts.
- Measured in square meters (m²) or square inches (in²).
Pressure-Area Relationship:
- Decreasing area increases pressure.
- Increasing area decreases pressure.

Atmospheric Pressure: The weight of the air above a surface, exerting force.
- Units: Pascals (Pa) or atmospheres (atm).
- Standard sea level pressure: 101,325 Pa or 1 atm.
Factors Influencing Atmospheric Pressure:
- Altitude: Increases in elevation lead to decreases in atmospheric pressure.
- Weather Patterns: Variations in atmospheric pressure correlate with changes in weather.
- Temperature Changes: Affects the density of air, thus impacting atmospheric pressure.