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AP Physics
Physics – the study of matter,
interaction and change. (Really
its all about the energy!)
Law and Theory
• A law is a description of nature that
manifests itself in recurring patterns of
events.
– The law of conservation of matter and energy.
• A theory elucidates (gives a clarifying
explanation) law and explains phenomena.
– The theory of evolution.
Classic and Modern Physics
• Everything developed up until the 1920-’s is labeled as
classical. It includes Newtonian Mechanics,
Thermodynamics, and Electromagnetic theory. Einstein
completed the pillars of classic physics with his theory of
relativity (special and general). The universe grinds
along in a certain way.
• When Einstein postulated that light is particulate and
new theoretical approach called Quantum Physics began
to develop. Modern physics studies the handful of
atomic particles (quarks, leptons and photons) that
compose the entire universe. Quantum Physics
understands the universe but nothing is certain.
Four Fundamental Forces
• Gravity – weakest, always attractive and not selective
and infinite
• Electromagnetic force – short range atomic interactions
which is infinite, attractive and repulsive and gives rise to
most contact forces.
• Strong Force – binds the quarks together to form
neutrons, protons and to form the nucleus
• Weak Force – turns quarks from one type to another and
change neutrons to protons. Thermonuclear fusion is
due to the weak force.
Symmetry
• Nature is symmetrical
• Theories are developed based on that
symmetry
• The infant Universe was symmetrical and
uncomplicated and has since shattered
into complexity as it has cooled.
MKS
• Length – always measured in meters.
• Mass – always measured in kilograms.
• Time – always measured in seconds.
• Mass is the quantity of matter and is a
fundamental quantity.
• Weight is the force a mass exerts based
on the gravitational acceleration at its
location.
Online Help
• Learnerstv.com
– Physics
• Classical Mechanics – Prof Lewin