Lecture Notes: Physics Fundamentals

Introduction

• Understanding the universe involves physics.
• Key concepts of gravity and motion.

Isaac Newton and Force

• Newton's Key Equation: Force = Mass × Acceleration
  • Force: Push or pull in a certain direction.
  • Mass: Amount of matter; measure of inertia.
  • Acceleration: Change in velocity over time.
• Predicting motion (e.g., basketball trajectory).

Law of Universal Gravitation

• Objects attract each other based on mass and distance.
• Key points:
  • Bigger mass = bigger pull.
  • Increased distance = decreased pull (inverse square law).
• Gravity causes planetary orbits around the sun.

Mass vs. Weight

• Mass: Constant irrespective of location.
• Weight: Depends on gravity; varies between Earth and Moon.

Energy Concepts

• Energy: Measured in Joules; has no direction.
• Types of Energy:
  • Kinetic Energy: Energy of movement.
  • Potential Energy: Stored energy due to position.
• Work: Force applied over distance; requires movement.
• Conservation of Energy: Energy cannot be created or destroyed, only transformed.

Thermodynamics and Entropy

• Entropy: Measure of disorder in a system.
  • Example: Ice cube melting increases entropy.
• The universe trends towards higher entropy.
• Energy forms vary in usefulness (e.g., gasoline vs. exhaust gases).

Electric Current and Charge

• Electric charge: Positive, negative, or neutral.
• Current: Flow of electrons; measured in amperes.
• Voltage: Electric potential difference that pushes current.
• Resistance: Opposition to current flow.
• Coulomb's Law: Charge interaction similar to gravitational attraction.

Maxwell's Equations

• Electric and magnetic fields are interconnected.
• Moving charges create magnetic fields; moving magnets create electric fields (induction).
• Electromagnetic waves radiate from charged particles.

Atomic Structure

• Atoms: Composed of protons, neutrons, and electrons.
• Isotopes: Variants of elements with different neutron counts.
• Half-life: Predicts decay rates of unstable isotopes.

Speed of Light and Quantum Mechanics

• Light travels at 299,792,458 m/s in a vacuum; behaves as both wave and particle (photons).
• Photoelectric effect: Light consists of packets of energy.
• Theory of Relativity: Time is relative; mass and energy are interchangeable (E=mc²).

Fission and Fusion

• Fission: Splitting atomic nuclei for energy.
• Fusion: Combining nuclei to release energy.

Quantum Mechanics Principles

• Superposition: Particles exist in multiple states until measured.
• Heisenberg's Uncertainty Principle: Cannot simultaneously know exact position and momentum of a particle.
• Double Slit Experiment: Demonstrates wave-particle duality; particles interfere with themselves when not observed.

Conclusion

• Physics helps us understand the universe's workings.
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