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37 Cards in this Set
- Front
- Back
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work
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done whenever a force is exerted over a distance. equal to the force that is exerted multiplied by the distance over which it's exerted. (=force x distance). measured in newton-meters (Nm) joules.
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joule
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amount of work done when a force of one newton is exerted over a distance of one meter. (=1N x 1M) (=1Watt x 1 sec)
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energy
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the ability to do work. measured in joules. (=power x time)
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power
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measures both the amount of work done (amount of energy expended & time taken to do that work (or expend that energy). rate @ which work is done or energy is expensed. (=work/time)
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Watt (W)
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unit of power equal to 1 joule/1 second.
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kinetic energy
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energy of movement (including heat & wave energy) (=.5 x mass x velocity^2). proportional to mass. (thermal, wave, solar, seismic...)
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potential energy
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energy waiting to be used. (chemical, electrical, elastic, magnetic)
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gravitational potential energy
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weight times height
mass (kg) x g (m/sec^2) x height (m) |
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types of potential energy
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chemical, electrical, elastic, magnetic
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radioactivity
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early 20th century discovery
mass is a form of energy |
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potential energy
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product of an object's mass times a constant (speed of light squared)
e=mc^2 |
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c
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speed of light, a constant equal to 3x10^8 m/sec
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interchangability
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the many different forms of energy are interchangeable
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photovoltaics
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field of research about conversion of solar energy into electrical energy via semiconductors
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trophic level
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all organisms that get teir energy from the same source
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1.79 x 10^17
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the lighted hemisphere of the earth receives each second _____ watts
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partitioning of solar energy
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25% reflected from atmosphere back into space
25% absorbed within atmosphere 5% reflected from Earth's surface back into space 41% heats the ground, water, % air (evaporation) 4% used in photosynthesis (supplies earth's entire food chain) |
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first tropic level
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plants that photosynthesize solar energy to make plant tissue & food
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second tropic level
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herbivores that eat plants only
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third tropic level
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carnivores that eat herbivores
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fourth tropic level
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carnivores that eat other carnivores
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decomposers
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organisms that eat dead tissue
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omnivores
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span trophic levels & eat plant & animal tissues
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plants
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transform @ most 10% of solar energy to tissues & chemical energy
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herbivores
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tissues retain only about 10% of energy derived from solar in plants (10% of 10% is 1% of original solar energy)
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carnivores
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retain only 10% from herbivores so only .1% of original solar energy
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10:1
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predator prey ratio (mass ratio of plants to support populations of herbivores & a predator to prey ratio among herbivores & carnivores)
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conservation law
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deals with constant and unchanging attributes of the universe
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system
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an imaginary box into which energy & matter is put for the purposes of study
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open system
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can exchange matter & energy with its surroundings
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closed (isolated) system
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can't exchange matter & energy with its surroundings
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thermodynamics
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study of the transfer of heat, work, and energy
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law of conservation of energy
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(first law of thermodynamics) in an isolated system, the total amount of energy, including heat energy, is conserved (kind of energy may change, but not the amount)
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fossil
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"something dug up" evidence of past life
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fossil fuel
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carbon-rich deposits of ancient life that burn with a not flame and thus release chemical potential energy of fossil material
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types of fossil fuels
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coal, oil (petroleum), natural gas, oil shale, frozen methane
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non -renewal resources
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there is a finite amount of these materials & once they are used up, there are no more on earth (fossil fuels)
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