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Energy is defined as?
Capacity to work.
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Potential energy is?
- Stored Energy
- ex. Nuclear, Fuels
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Kinectic Energy is? Example?
- Energy in Motion.
- Ex. Wind, Riding Bike
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Global demand for energy has ______ in the past 50 years and might ______ in the next 30 years.
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The first modern oil well was drilled in Pennsylvania in ______
1859
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Two approaches to energy conservation?
- Technical Fix
- Ex. More efficient engines
- Lifestyle Change
- ex. Turning down Thermo
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Motion is _______ of an object and basic terms associated with it is ______ and ________
- Displacement
- Speed- change of distance
- Velocity-Rate of change
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Force causes the _______ of an object to change. The angular counterpart of force is _______.
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Rotational motion measures in angular ______ ex.______., Rotational_______ ex.______ and rotational ________
- Displacement
- ex. Degrees and Rads
- Rotational Velocity
- ex. RPM
- Rotational Acceleration
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Mass is the measure of an objects _______ to move.
objects SLUGGISHNESS to move
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Rotational Mass rule of thumb is, The ______ mass is from center the more sluggish.
Further
- EX. Sphere Vs DISK Vs RING
- SPhere 1st Place
- DISK 2nd
- Ring 3rd
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Newtons 1st law of Motion says.....
An object in motion stay in motion( or not in motion) unless acted upon by outside forces!
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Newtons 2nd Law of motion says.....
(hint) a=f/m
An objects acceleration is directly proportional to the net force acting on it and inversely proportional to its mass.
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Newtons 3rd law of motion says...?
- For every action force there is an equal and opposite reaction force.
- i.e. pushing on a wall.
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Work is ....?
- Work= Force x Distance
- or
- W=FxD Expressed in Joules
- Ex. Throwin, Running, walking can of coke up stairs
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Power is defined as.....?
- Power= Work/Time
- Or
- P=W/T Expressed in Watts
- Ex. How Fast I get can of coke up stairs
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3 types of Energy Systems
Open=Mass & Energy allowed to flow across
- Closed=Energy allowed to flow
- MASS not allowed
Isolated=No Mass or Energy allowed to flow
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Efficiency is defined as....?
- Efficiency=Useful energy output
- Total Energy Input
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To Find overall Efficiency....
- multiply the product of individual efficiencies.
- Ex. .35*.9*.05=1.6% overall efficiency
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Principle of conservation of energy is stated as...?
Examples:
- The energy into a system equals to the energy that leaves plus the increase of energy stored in the system.
- Ex. Solar house- Energy coming in is equal to energy leaving plus the energy stored in concrete, walls, floors etc.
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What is the energy inputs and outputs of fossil fuel plant?
Inputs: Fuel, air for combustion, Cooling Water(to Condenser)
OutPuts: Electrical Energy, hot water(from condenser), gases through stacks
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Rankin cycle is defined as....?
A cycle in which the working fluid changes state.
Example: Steam turbine engine
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Gas cycle is defined as...?
A cycle in which the fluid is a gas at every point.
Ex. Internal Combustion Engine
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First Law of Thermo's states that.....?
(Hint):Think of Principle of conservation of Energy!!
- work done plus heat added is equal to the change in total energy of the system!
- Remember: q=Heat
- W=Work
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Greater Specific Heat=Greater Thermal Storage
Example of Specific Heat?
WATER
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Phase Change: Latent Heat
- Latent Heat is heat added during phase change
- ***** NO TEMP CHANGE
- ****Graph LEVELS OFF "-------"
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Phase Change:Fusion Heat is...?
- Heat added to convert from solid to liquid.
- ****THERE IS TEMP CHANGE
- ***Graph LOOKS LIKE "/?
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Phase Change: Heat of Vaporization is...?
- Heat added to convert from liquid at its boiling point to gas
- *****There is Temp Change
- ****Graph looks like this "/"
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Conduction is a mode of heat transfer where...?
EXample?
Heat is transferred through molecular collisions from a hot object to a colder one.
Ex. A spoon handle heating up in pot of boiling water!
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The closer objects are in temp the Faster/slower conduction will occur?
Slower!!!
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Heat Transfer Modes: Convection is...?
Ex.
- The transfer of heat through a material by the movement of the material.
- Ex: Convection Currents-Hot air rises and replaced by cold air and so on.
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Two types of Convection are....?
Natural-Relies on density is less @ higher temp.
Infiltration (homes)- Air leaks through electrical outlets etc.
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Moes of Heat Transfer: Radiation is...?
Example?
Radiation is the transfer of energy by the emission of electromagnetic waves which carry energy away from emitter.
Ex. Heat exhausted by a hot water radiator.
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The higher energy an emitter is the Longer/shorer the wavelength?
The higher energy an emitter is the SHORTER the WAVELENGTH
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The 2nd Law of Thermos says...?
- 4 an isolated system Entropy can Increase
- 'Heat can flow spontaneously only from a hot source to a cold sink
- ''No heat engine can be constucted in which heat from hot source is converted entirely to work. Some Work must go to lower colder sink!!! ENTROPY
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Entropy and the 2nd law of thermo's says that...
Entropy aka disorder may only increase. Unless there is work put into a system then and only then will entropy decrease.
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NEVER have 100% Efficiency unless your Carnot who represents the PERFECT ENGINE calculated by
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Question? Using Carnot Equation m=Th-Tc
Th
what is the max efficiency of plant if the temp of the steam is 540'C. The Temp of Cold Reservoir is 20'C.
- 1st: Convert both temps to Kelvin!!!! Must be in Kelvin!!!!
- -540'C = 813'K
- - 20'C= 293'K
- 2nd: Enter Into Equation: 813'K-293'K
- 813'K
- 3rd: Answer is .64 or 64%
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