1A:
Basics of Physics
& Newton's Laws
Feynman Simplified
1A covers about
the first quarter of the freshman course of The Feynman
Lectures on Physics. The topics we explore include:
 What is science
 Basics of Physics
 Conservation of
Energy
 Motion
 Newton's Laws
 Work
 Potential Energy
Excerpt:
QED
Quantum
Electrodynamics (QED) is our most advanced model of electromagnetism,
incorporating all the discoveries of special relativity and quantum
mechanics. QED says that the force between two charged particles is
caused by their exchange of photons, as sketched below:
Figure 21
Electrons Exchanging a Photon
Figure
21 is a schematic representation of two electrons repelling one
another through the electromagnetic force. The time axis is vertical:
time increases from the bottom to the top. The horizontal axis
represents the distance between the electrons. Neither axis is intended
to be quantitative; only the sequence of events is important. As the
electrons (e–) approach one another, the left electron emits a photon
(a particle of light) that is subsequently absorbed by the right
electron. QED posits the photon transfers energy and momentum from one
particle to the other, which results, in this case, in a repulsive
force.
