Physics 33 is a course that covers the fundamental principles of particle physics. One of the topics covered in this course is the four basic forces of nature: gravity, electromagnetic force, weak nuclear force, and strong nuclear force . These forces are responsible for all the interactions between particles in the universe.
Gravity is the weakest of the four forces and is responsible for the attraction between massive objects. Electromagnetic force is responsible for the interaction between charged particles and is much stronger than gravity. The weak nuclear force is responsible for radioactive decay and is much weaker than the electromagnetic force. The strong nuclear force is responsible for holding the nucleus of an atom together and is the strongest of the four forces .
Particle physics is intimately tied to these four forces. Certain fundamental particles, called carrier particles, carry these forces, and all particles can be classified according to which of the four forces they feel . The table below summarizes important characteristics of the four basic forces:
| Force | Approximate Relative Strength | Range | Carrier Particle |
|———–|———————————|———–|———————-|
| Gravity | 10^-38 | ? | Graviton (conjectured)|
| Electromagnetic | 10^-2 | ? | Photon (observed) |
| Weak Nuclear | 10^-13 | <10^-18 m | W+, W-, Z0 (observed) |
| Strong Nuclear | 1 | <10^-15 m | Gluons (conjectured) |
The search for a correct theory linking the forces, called the Grand Unified Theory (GUT), is explored in this course in the realm of particle physics. The unification of forces follows a long tradition. In the 19th century, the distinct electric and magnetic forces were shown to be intimately connected and are now collectively called the electromagnetic force. More recently, the weak nuclear force has been shown to be connected to the electromagnetic force in a manner suggesting that a theory may be constructed in which all four forces are unified .
Force Diagram Physics 33 image
