PHYS 110A Lecture Notes - Lecture 1: Test Particle, Torsion Spring, Magnetostatics
Document Summary
Office hours: m 2:30-3:30, r 9:15-10:15 in broida 4105. Read chapter 1 as you are expected to know it. Although it will not covered, it will be used. Four realms of mechanics: slow & big: classical (newtonian) slow & small: quantum fast & big: special relativity fast & small: quantum field theory. Four forces: strong, em force, work, gravitational. Almost all we feel are covered by em force (except gravity) Em forces are generally much stronger than gravity. Field theory field: e field is a map of force transmitted to a test charge. Comes in two flavors (+ and -) 2. Forces are linear to charge so we can invoke linear superposition of forces. Coulomb used a torsion balance to measure the deflection of two charged balls. Test charge in the center of 12 positive charges in a circle. Net force on middle charge is zero due to symmetry.
