Classical Physics The Foundation of pure applied macroscopic
- Slides: 12
Classical Physics – The Foundation of pure & applied (macroscopic) physics & engineering! – Newton’s Laws + Boltzmann’s Statistical Mechanics (& Thermodynamics): Describe most of the macroscopic world – Classical Mechanics: The Physics of the 17 th & 18 th centuries. Still useful! – High speeds (v ~ c): Special Relativity: 20 th century physics! – Small size (atomic & smaller): Quantum Mechanics: 20 th century physics! Physics 5301!
Mechanics • HOW objects move (behave) under given forces. • (Usually) Does not deal with the sources of forces. Answers the question: Given the forces, how do objects move? • Forces are classified into 4 types: Four Fundamental Forces Of Nature! Mechanics applies to all four!
4 Fundamental Forces of Nature Sources of 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)
4 Fundamental Forces of Nature Sources of the forces, in order of decreasing strength
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 Force were combined into one theory. S. Weinberg & A. Salaam: 1972 Nobel Prize in Physics!
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.
Standard Model
Standard Model
Standard Model
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 BOTH the Classical Mechanics & the Quantum Mechanics world! – The major LINK between microscopic & macroscopic physics! – Contains Thermodynamics as a sub-theory!