Physics 100
Lecture 2, May 14, 2010
N. Alberding
Mastering Physics
• Course ID is SFUPHYSICS100E
• Can buy stand-alone Mastering Physics
codes at bookstore.
• http://www.masteringphysics.com
• Knight, Jones and Field, College
Physics, 1st edition.
The Speed of Earth
• How fast does the surface of the earth
move?
• To make it easy, assume we’re on the
equator.
• Vancouver is at 50° N; how does that
change the answer?
Puzzle
• You’ve been told that the earth rotates
• But it really looks like the sun goes
around the earth
• Why believe what you’ve been told?
• Why doesn’t a ball come down far away
when it’s tossed up in the air?
• Answer coming…..
Why Mathematics?
• Compact language
• Logic is embedded in the language.
• The Travellers’ Tale
• how non-mathematical language can
confuse logic.
Kinematics
• Using math to describe motion
• Start with space
• Then do time….
Space
• What is distance?
• Operational Definition
• Define in terms of an operation that
allows its measurement
Distance
• Establish a standard “stick” for the unit
of distance.
• Measure how many sticks fit between
two points.
• take the path that gives the smallest #
• Subdivide the stick into subunits for
more precision.
The Metre
• After the French revolution they decided
to use the earth as the standard
• hopefully neutral, no objections
• Define N. Pole to Equator = 10 000 000
m
• through Paris (not so neutral?)
• they actually measured the distance
from Dunkirk (51°N) to Barcelona
(41°N) and figured it out.
Triangulation