Quarter 1 Flashcards
energy
energy of motion (kinetic)
F=1/2mv^2 (Joules)
mass- kg
v- m/s
OR
powertime
ie. J=KWhour
heat energy
1cal = 4 J
Power
power (W) = energy/time (J/s)
1 MW
1*10^6
1 KW
1*10^3
US energy consumption
- Petroleum (35%)
- Natural Gas (31.3%)
- has increased a lot
—————- 1/3 - Coal (10.5%)
- has decreased a lot - Nuclear (8.13%)
- nuclear>renewable
—————— 1/10 - Biomass (4.83%)
- Wind (3.33%)
- Hydro (2.28%)
- Solar (1.5%)
- Geothermal (0.206%)
-renewables have seen major increases (10 yr)
Efficiency
(Useful energy out/ Energy in) < 100%
Heat is most common excess energy
Transportation and alt. energy
boats are most common because weight isn’t a problem - nuclear
Navy- ships/submarines (now only limiting factor for being underwater is food supply/dont need air for energy)
Common energy source tradeoffs
1.costs 2.availibility 3.danger
coal
cheap and abundant
0.4 cents and deposits across the world bc its a fossil fuel
burning -> sulfuric acid -> acid rain + CO2
coal mines are soft and dangerous
fossil fuels
mostly from plants
coal 0.4c, natural gas 0.7c, petroleum (gas 7c)
natural gas
hydrocarbons make less greenhouse gasses
US lowered gg from switching
-whereas problem with natural gas is its volume
C-> CO2
CH4-> CO2 + H20
petroleum (oil)
mix of hydrocarbons (lite CH4 gas, heavy liquid)
refined for different types of fuel
+42,000 J/G compact form of energy
-expensive and gives off CO2 (less than coal)
US is leading producer of oil
production of oil
US only and main until 1940s
Saudi Arabia top 1980s
US largely self dependent for oil
Global East doesn’t produce much
political bc not evenly distributed across world
nuclear power
nuclear fission heat -> boils water for steam
steam creates energy to drive an electric turbine
+produces no greenhouse gas and minimal air pollution
- fear around nuclear power, expensive, radioactive waste
Renewable Energy
solar power, wind power, hydroelectric, geothermal
solar power
photoelectric effect
panels are 15-40%
+ no moving parts, easy setup, no waste
- not available all the time (daylight/not cloudy), cost/efficiency
are getting cheaper and more efficient w time
wind power
runs a turbine
+ no emissions, and no running out
- noisy, hazard to birds, not evenly distributed, costly
great plains is best location
hydroelectric power
2% of power is static because we have used all ideal locations
+ relatively cheap, more reliable
- not many locations (river and dam are perfect conditions the Pacific NW), largest types of power plants, dams can be bad for ecosystem
geothermal
caves are about 55 degrees F all year
deeper caves get warmer and can use their heat energy
2 locations: geysers in Yellowstone, Iceland is 25% of energy source
not very practical for US 2% of energy source
Nuclear Fusion
energy of the future and will always be
Food Energy
100 Cal = 100,000 calories = 400,000 Joules - if it was immediate
Bomb Calorimeter
burning up food to see how much heat given up
Fermi Estimation
overestimate and underestimate
0th Law of Thermodynamics
hotter goes to colder body
Convection
moving gas or liquids (warm up a bathtub or oven)
Conduction
vibration of molecules transferring from regions (conductors of heat may feel cold bc conducting heat out of body bc its more efficient)
Radiation
heat being turned into lightwaves and depositing energy elsewhere (carport)
Units
____ F C K
Boil 212 100 373
Freeze 32 0 273
-460 -273 Absolute 0
Conversion F to C
C = 5/9(F-32)
Challenger (1986)
disintegrated upon takeoff due to O Rings freezing and losing elasticity
Columbia (2003)
disintegrated upon re-entry
when slowing down KE turned into heat energy
T= (300K) M^2
M- speed of sound fraction
T- temperature in K
Space Shuttle Incidents
Challenger
Columbia
Apollo 13
Apollo 13
coated with a layer of resin that vaporizes and carries heat away from capsule upon re-entry
THRU convection
Moon Landing
just need retro rocket spring to disperse KE
Water Thermal Expansion
expands as it cools until freezing point the crystal structure is tremendously large
1st Law of Thermodynamics
energy is conserved
2nd Law of Thermodynamics
useful energy is converted into heat
- efficiency is always less than 100%
- entropy (disorder of universe) always increases
(unpredictability)
3rd Law of Thermodynamics
can never reach absolute zero
Normal Distribution/ Gaussian/ Bell Curve
μ - mean, average will always be peak
σ - width of distribution
±1 68%
± 2 95%
± 3 99.7%
Not examples of normal distribution
height of basketball players - height bias and biological limit to height so it is not evenly distributed
household income distribution- income can be unlimited
financial markets- highly non-Gaussian
standard deviation calculation
sqrt(N) when N is number of things counted
wave length
distance between two hills or troughs (λ, L)
frequency
the amount of time it takes to move, rate of oscillation (f = cycles/sec)
amplitude
height of a wavelength
speed equation (lightwaves)
speed= frequencywavelength
c= Lf
Lf - inversely proportional
c= 310^8 m/s (light always travels at the same speed)
Electromagnetic Spectrum
radio waves
microwaves
infrared radiation
visible light (ROYGBIV)
ultra violet
x-rays
gamma rays
FM
frequency modulation (MH)
3 m
clear line of sight
typically music
increased frequency = an increased amount of information can carry
doesn’t carry as far as AM
wavelengths that are small compared to obstacle can’t bend around
AM
amplitude modulation (KH)
200-500 m
typically talk shows, sports, media
carriers very far especially at night during the summer
sound transmits around physical barriers
ground wave propagation-produce electric currents through the ground
ionosphere- layer of ionized radiation, bounce off F layer like a mirror
-switches to lower power at night so there won’t be interference across cities
-clear channels- no one else can broadcast so that there can be national radio stations
Microwaves
L= 3mm->0.3m
line of sight
radio detection and ranging
Doppler Radar- speeding calculated by compression or stretch of the wave received
air plane stealth
Microwave Devices
microwaves and wi-fi operate at 2.45 GHz so they don’t interfere w/ everything else
jiggles around polarized molecules
cellphones-operate on various frequencies depending on carrier
4G Verizon -700 MHz
5G - 30 GHz
phones are transmitters of microwaves as well as receivers
microwaves are not ionizing so it can cause cancer
no scientific evidence can cause brain cancer
Infrared Radiation
heat radiation i.e., night vision goggles
micron 10^-6
hotter things increased in radiation
L = 300K/T
peak emission 3000K/degrees K
Uses
night vision goggles
contactless thermometer
heat seeking missels
pit-vipers use for hunting
tv remote
Visible Light
spectrum peaks in visible in spectrum emission 47%
Ultraviolet
2% UV in solar spectrum
white colors can fluoresce
UV mostly gets absorbed by atmosphere because in the upper atmosphere, UV hits O2 and then can create O3 (ozone), prod and absorbed by UV
UV is higher so re-emits as visible light
Freon
chloroflorocarbon, is stable until its hit by UV, then it destroys ozone and led to the ozone hole at S pole
Montreal Protocol
banned chlorofluorocarbon and was a great success bc there are easy substitutes
X-Ray
10^-9 nm
production- taking beam of electron and slamming into a target to emit an x-ray beam
soft: less energetic and less penetrative so soft tissue will absorb (more dangerous)
hard: medical purposes
- led aprons have 1/2 mm of led to block x-rays-> high on periodic table of dense
CAT/CT Scan: 3D imaging computer tomography
Gamma Radiation
Background radiation-cosmic radiation
uranium emission in glaze
