Physics: Energy, Force, and Motion

Energy and Force

Gravity

• Force that attracts two objects with mass towards each other
• Strength of gravity depends on mass of objects and distance between them
• On Earth, gravity pulls objects towards the center with an acceleration of 9.8 m/s^2

Kinetic Energy

• Energy of motion
• Depends on the mass and velocity of an object
• Formula: KE = 0.5 * m * v^2
• Units: Joules (J)
• Examples: rolling ball, moving car, flying airplane

Potential Energy

• Stored energy that can be converted into kinetic energy
• Types:
  • Gravitational potential energy: energy of an object due to its height or position
  • Elastic potential energy: energy stored in stretched or compressed materials
• Formula: PE = m * g * h (for gravitational potential energy)
• Units: Joules (J)
• Examples: ball at the top of a hill, stretched rubber band

Friction

• Force that opposes motion between two surfaces in contact
• Types:
  • Static friction: prevents an object from moving
  • Kinetic friction: slows down an object in motion
• Factors that affect friction:
  • Surface roughness
  • Normal force (force pressing surfaces together)
  • Type of surface (e.g. wood, metal, rubber)
• Formula: F_f = μ * N (where μ is the coefficient of friction and N is the normal force)

Test your understanding of fundamental physics concepts, including gravity, kinetic energy, potential energy, and friction. Learn how to calculate energy and force, and understand the factors that affect motion.