college physics chapter 1 introduction. science is a philosophy it is not science without data it is...
TRANSCRIPT
College Physics
Chapter 1Introduction
Science is a Philosophy It is not science without data It is not science without
measurement errors (somehow) It is not science unless it can be
reproduced (objectivity) Math is like the grammar of
science
Fundamental Quantities and Their Dimension Length [L] Mass [M] Time [T]
other physical quantities can be constructed from these three
Systems of Measurement Standardized systems
agreed upon by some authority SI -- Systéme International
1960 by international committee main system used in this text also called “mks” units
cgs – Gaussian system US Customary
nits of common usage
Prefixes Metric prefixes correspond to
powers of 10 Each prefix has a specific name Each prefix has a specific
abbreviation See table 1.4
Structure of Matter
Dimensional Analysis Technique to check the
correctness of an equation Dimensions (length, mass, time,
combinations) can be treated as algebraic quantities add, subtract, multiply, divide
Both sides of equation must have the same dimensions
Uncertainty in Measurements There is uncertainty in every
measurement, and uncertainty carries over through calculations
Lab uses rules for significant figures to approximate the uncertainty in calculations
Conversions Units must be consistent (time=time) Units carry value! (1 m = 100 cm) You can manipulate words in equations
just like you manipulate numbers Example:
Cartesian coordinate system
Also called rectangular coordinate system
x- and y- axes Points are labeled
(x,y)
Plane polar coordinate system Origin and reference
line are noted Points labeled (r,) Point is distance r
from the origin in the direction of angle , (counterclockwise from reference line)
Trigonometry Review
More Trig Pythagorean Theorem
To find an angle, you need the inverse trig function for example,
Be sure your calculator is set appropriately for degrees or radians
Must beware of quadrant ambiguities
Polar Coordinates Example Convert the
Cartesian coordinates for (x,y) to Polar coordinates (r,)
How High Is the Building? Determine the height of the building
and the distance traveled by the light beam
Problem Solving Strategy