Chapter 1: Measurements and
DImensional Analysis
Units
Kilograms
mass
Meters
Seconds
Charge of an electron = 1.602 x 10^-19 Coulumb
length
volume
density = mass/volume #
helpful things about units
1 kg = 2.2046 pounds
1 inch = 2.54 cm exactly
Celsius (Kelvin)
about pi x 10^7 seconds in one year
density of water = 1 g/cm^3 = 1000 kg/m^3
WolframAlpha
density of air (sea level) is 1/1000-th of water
What is the volume of this classroom?
What is the mass of air in this classroom?
speed of light = 3 x 10^8 m/s
How far will light travel in one year?
Convert 1 femtolight year to yards (football)
prefixes
giga = 10^9
mega = 10^6
human civilization uses 15 terawatt (2017)
What is the volume of 1 meter times area of the oceans?
tera = 10^12
micro = 10^-6
nano = 10^-9
pico = 10^-12
femto = 10^-15
humans just barely float in water: density = 1 g/cm^3
Significant Digits
multiplication
exact numbers
addition
Precision and Accuracy
Energy
kinetic energy
potential energy (work)
chemical energy