Mechanics: “Classical” Mechanics

Mechanics: “Classical” Mechanics “Classical” Physics: “Classical”   Before the 20th Century The foundation of pure & applied macroscopic physics & engineering! Newton’s Laws + Boltzmann’s Statistical Mechanics (& Thermodynamics):  Describe most of macroscopic world! However, at high speeds (v ~ c) we need Special Relativity: (Early 20th Century: 1905) Ch. 14 of M&T Also, for small sizes (atomic & smaller) we need Quantum Mechanics: (1900 through ~ 1930) Physics 4307! “Classical” Mechanics: (17th & 18th Centuries) Still useful today!

Four Fundamental Forces Of Nature! Mechanics The science of 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 four types: Four Fundamental Forces Of Nature! Mechanics (in some form) applies to all four!

The 4 Fundamental Forces of Nature The Sources of these 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)

The 4 Fundamental Forces of Nature The Sources of these forces: In order of decreasing strength

The 4 Fundamental Forces of Nature “Electro-Weak” Force Since ~ the late 1960’s, in some sense have reduced the 4 fundamental forces to 3! The Electromagnetic Force & the Weak Nuclear Force were combined into one theory. S. Weinberg & A. Salaam: The 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! Statistical Mechanics: (Physics 4302) What we’ve mentioned is  all of physics except: Statistical Mechanics: (Physics 4302) The mechanics of systems with huge numbers of particles (>> ~ 1023). Uses probability & statistics methods to calculate the macroscopic properties of a system from the microscopic force laws between the particles. The major LINK between microscopic & macroscopic physics! Contains Thermodynamics as a sub-theory!