Download Pre-Newtonian

Pre-Newtonian
Chapter 1 & 4
Dr. Ray Kwok
SJSU
Intoduction - Dr. Ray Kwok
What is Science?
Capable of explaining past events and predicting future events with a
given set of parameters
(repeating pattern of sunrise, sunset, phases of the moon…etc)
Can be formulated into theory or hypothesis
(Earth is a globe & self-spinning)
Can be tested
(observed the appearance of mask on sail boat,
sailed around the Earth,
observed coriolis effect…)
Example – is the following statement scientific?
“It is quite possible that in some other galaxy the laws of physics are
fundamentally different than the laws we are acquainted within this
galaxy.”
Intoduction - Dr. Ray Kwok
What is Physics?
A natural science – study of the universe, law of nature..
unlike e.g. social science.
A physical science – a branch of natural science
studying non-living systems, unlike e.g. biology
Physics = “nature” in Greek, study of motion and
spacetime, and anything associate with it such as
energy and force.
Is a general analysis of nature; a study of our world and
universe and how things behave.
A ball game? Meet Paul Hewitt…
Intoduction - Dr. Ray Kwok
Physics & Math
Math is a powerful tool (language) for abstract
reasoning
Physics without Math
negative number, square root, complex…
Music without notes or music theory, not ideal but...
Units:
SI units [Systéme International], or mks units
cgs units
British units (ft, lb, sec)
Important for communicating info !
Intoduction - Dr. Ray Kwok
Pre-Newton
mostly descriptive
Johnannes Kepler
1571 – 1630, Germany
Planetary Motion (Ch.10)
Mathematics, Optics
Aristotle
384 – 322 BC
Greek philosopher,
Systematic - physical science
Force →unnatural motion
Archimedes
287 – 212 BC, Syracuse
Greek scholar
Math – infinite series
Phys, Engr,
Astronomy, Invention,
Fluid (Ch. 13)
Galileo Galilei
1564 – 1642, Italy
Improved Telescope
Math, Phys, Astronomy
Father of Science
Father of Astronomy
Intoduction - Dr. Ray Kwok
Galileo
Leaning Tower of Pisa
Falling rate independence of mass (weight) –
except for the small air resistance effect
visit
Exploratorium
Intoduction - Dr. Ray Kwok
What is air resistance?
Air trying to slow down the motion of moving
object
Proportional to speed ( ~v2 )
Proportional to size (cross-sectional area)
Intoduction - Dr. Ray Kwok
Question?
5 legs??
Including air resistance, which one hit the ground first?
Which one experiences a greater air resistance?
Intoduction - Dr. Ray Kwok
How about a golf ball &
styrofoam ball (same size)?
Including air resistance, which one hit the ground first?
Which one experiences a greater air resistance?
Intoduction - Dr. Ray Kwok
Next…
Read Ch 2 to 4