# Physics I Class 18 Coulombs Law 1 Forces

• Slides: 23

Physics I Class 18 Coulomb’s Law 1

Forces Known to Physics (Review) 2

A New Property of Matter Charge 3

Conservation of Charge 4

Coulomb - A Man, A Unit, A Law 5

Coulomb’s Law of Electrostatic Force 6

Direction of Electrostatic Force “Opposites Attract” 7

Properties of Electrostatic Force Similarities with Gravity 8

Properties of Electrostatic Force Differences with Gravity 9

Comparison of Gravity and Electrostatic Force 10

Superposition of Electrostatic Forces 11

Two Ways of Calculating the Electric Force Vector 12

Class #18 Take-Away Concepts 13

Class #18 Problems of the Day 14

Class #18 Problems of the Day 15

Activity #18 Coulomb’s Law 16

Class #18 Optional Material A Prof. B’s Method of Calculation 17

How to Calculate a General Unit Direction Vector A “unit vector” is a special vector with dimensionless length of one unit. 18

How to Calculate the Electric Force Vector (Prof. B’s Method) 19

Class #18 Optional Material B “Three Quarks for Muster Mark” 20

“Elementary” Particles An Embarrassment of Riches Beginning with the discovery of the electron in 1898, physicists encountered an increasing array of so-called “elementary” particles. It became evident to physicists in the 1960’s that these particles must themselves be combinations of deeper fundamental particles. Joseph F. Alward, Ph. D Department of Physics University of the Pacific 21

The Origin of Quark Theory 1929 - Murray Gell-Mann took the name quark from "Three quarks for muster Mark", in James Joyce's book Finnegan's Wake. (1963) (Nobel Prize 1969) In the early 1960’s, Gell-Mann and others proposed the Quark Theory to explain the “elementary” particles and their interactions in terms of 3 deeper fundamental particles called quarks. Further developments have shown there actually 6 different quarks and their corresponding anti-quarks. The quarks and their properties have been given whimsical names like “charm” that have no physical significance. 22

6 Quark Building Blocks Quarks Anti-Bottom 23