Concept Builder Notes: Types of Forces and Pressure in Daily Life
🔹 Types of Forces
Forces can be categorized based on their interaction as:
- Contact Forces: These act when objects are physically touching.
- Frictional Force: Opposes motion between surfaces.
- Muscular Force: Applied by human or animal muscles.
- Tension Force: Force through strings or ropes.
- Normal Force: Perpendicular force from a surface.
- Non-Contact Forces: These act from a distance without physical contact.
- Gravitational Force: Pulls objects toward the Earth.
- Magnetic Force: Between magnetic materials or magnets.
- Electrostatic Force: Between charged objects.
Example: A falling apple experiences gravitational force. A rubbed balloon attracts bits of paper due to electrostatic force.
🔹 What is Pressure?
Pressure is defined as the force applied per unit area.
Pressure = Force / Area (Unit: pascal or Pa)
Pressure = Force / Area (Unit: pascal or Pa)
🔹 Pressure in Daily Life
- Knives: Have sharp edges to concentrate force on a smaller area, increasing pressure for easier cutting.
- Nails: Pointed tips reduce area, increasing pressure to drive them into walls.
- Elephants vs Camels: Camels have broad feet to reduce pressure on sand and prevent sinking.
- School Bags: Wider straps distribute force, reducing pressure on shoulders.
🔹 Liquid Pressure
Pressure in liquids increases with depth and acts in all directions.
Example: Dams are built thicker at the bottom because water pressure increases with depth.
🔹 Gaseous Pressure
- Gases exert pressure on the walls of their containers.
- Used in inflating tires, spray cans, pressure cookers.
💡 Tip: Pressure is crucial in medical syringes, hydraulic lifts, and even breathing!
