Classical Physics

2. Classical Physics • The Foundation of pure & applied (macroscopic) physics & engineering! • Newton’s Laws+ Boltzmann’sStatistical Mechanics(& Thermodynamics): Describe most of the macroscopic world • Classical Mechanics: The Physics of the 17th & 18th centuries. Still useful! • High speeds(v ~ c):Special Relativity: 20th century physics! • Small size (atomic & smaller):Quantum Mechanics:20th century physics!Physics 5301!

3. Mechanics • HOW objects move (behave) undergiven forces. • (Usually)Does not deal with the sourcesof forces. Answers the question: Given the forces, how do objects move? • Forces are classified into 4 types: Four Fundamental Forces Of Nature! Mechanicsapplies to all four!

4. 4 Fundamental Forces of NatureSourcesof the forces, in order of decreasing strength • Strong Nuclear Force: • Binds nuclei together. Still being researched. • Electromagnetic Force: • E&M phenomena. Chemical forces. Most everyday forces. Maxwell, Coulomb, Ampere, Faraday, ... • Weak Nuclear Force: • Nuclear decay. Fermi, Bethe, others. Still being researched. • Gravitational Force: • Newton (classical mechanics) • Einstein (general relativity)

5. 4 Fundamental Forces of NatureSourcesof the forces, in order of decreasing strength

6. 4 Fundamental Forces • The “Electro-Weak” Force: • Since ~ the late 1960’s, in some sense the 4 fundamental forces have been reduced to 3! • The Electromagnetic Force & the Weak Nuclear Forcewere combined into one theory. S. Weinberg & A. Salaam: 1972 Nobel Prize in Physics!

7. The Standard Model of Particle Physics The “Periodic Table for Elementary Particles”! Quantum Chromodynamics (QCD) and the Electroweak Theory Protons & Neutrons consist of 3 Quarks each.

8. Standard Model

9. Standard Model

10. Standard Model

12. The Rest of Physics! • What we’ve mentioned is  all of physics except: Statistical Mechanics:(This course!) • Mechanics of systems of huge numbers of particles (>> ~ 1023). • Uses Probability & statistics to compute macroscopic properties from microscopic force laws. • Applies to BOTHthe Classical Mechanics & the Quantum Mechanics world! • The major LINKbetween microscopic & macroscopic physics! • Contains Thermodynamics as a sub-theory!