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126 Cards in this Set
- Front
- Back
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force equals
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mass time acceleration
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a ______ is a push or pull
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force
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mass is
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total amount of matter in an object
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weight is
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measurement of gravity times a mass
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Torque is
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a force-like quantity in rotational mechanical systems
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Net force is
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the sum of all forces acting upon an object
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Prime movers
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force-like quantities in different systems
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Density is found by
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dividing mass by volume
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a hydrometer is used to ___________
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measure density or specific density in fluids
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Pressure is measured by
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dividng unit of force by unit of area
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manometers are used to
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measure pressure differences
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the two types of fluids are
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hydraulic and pneumatic
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gasses are ________, liquids are ________
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compressible, non-compressible
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pressure increases with _____ in a fluid
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depth
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absolute pressure is
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pressure measured in reference to a vacuum (zero pressure)
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weight density is
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the ratio of an objects weight to its volume
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Voltage comes in
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two forms known as DC (direct current) and AC (alternating current)
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voltmeters measure
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voltage difference
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multimeters measure
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voltage, amps, and ohms
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the positive pole on a battery is the ______. the negative end is known as the ________.
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anode, cathode
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electrical circuits contain
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a source, conductors, and a load. may also have a control element
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temperature difference
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acts as a prime mover in thermal systems
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heat is
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a form of energy
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temperature is
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the measure of the average energy of motion of molecules in a substance
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thermocouples use
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three wires of two different metals to measure temperature.
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the degree symbol is placed ______ of the F or C when giving temperature. It is placed _____ when giving temperature difference.
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in front of, behind
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work equals
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force times distance
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input work is
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work going into a system
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output work is
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work done by system
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efficiency is
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output work divided by input work, multiplied by 100
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spring scales are
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used to measure input and output force
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in rotational mechanical systems work is equal to
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torque multiplied by angle which lever arm moves
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the basic English unit of work is
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foot-pound
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the basis SI unit of work is
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newton-meter
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linear mechanical work is done when
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a mass is moved in a straight line
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angular mechanical work is done when
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a mass is moved around an axis of rotation
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mechanical work causes an object to
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start and stop moving and or change direction
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fluid work is equal to
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pressure difference time volume moved
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when given height fluid is raised ______ of fluid to calculate fluid work
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weight density
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in a closed fluid system
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fluid is reused
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there is no such thing as ____________ fluid work
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linear or angular
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pressure exerted by piston times area of piston face equals
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work done by piston
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cross sectional area of a cylinder can be found by
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multiplying .7854 by the diameter^2
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electrical work is done when
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voltage moves a specified amount of electrical charge
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one coulomb is equal to
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6.25 times 10^18 electrons
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electrical charge can be calculated by
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multiplying ampers by time
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the basic unit of electrical work is
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1 joule (1 volt * coulomb)
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input work performed by an electrical pump or motor will be given
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in joules
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a rate is a
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displacement divided by elapsed time
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velocity is the
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measure of linear mechanical work
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speed is
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scalar
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units of linear mechanical rate are
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Foot per second and meter per second
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angular rate is expressed in
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radians per second and revolutions per minute
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there are ____ radians in one revolution
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6.28
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a stroboscope is used to
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measure angular rate
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acceleration is
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the rate at which speed increases or decreases
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in fluid systems _______ is volume of fluid moved in a given period of time
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flow rate
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units of fluid flow are
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gallons/minute, cubic meters per second
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viscosity is
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quality of substance related to its thickness
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under the same pressure a larger pipe will have a _________ than a smaller pipe
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greater flow rate
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electrical rate is
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amount of charge moved in a given time
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electrical current flow is symbolized by an
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"I" and is measured in ampers
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one milliampere is equal to
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1/1000 amps
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one microampere is equal to
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1*10^-6 amps
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an ammeter is used to
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measure current
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hertz is a
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measure of frequency in alternating current
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an oscilloscope can measure
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frequency as well as voltage waveform
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heat flow rate is
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symbolized by Qh
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Heat flow rate is
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amount of heat energy transferred through a substance in a unit of time
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units of heat are
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Btu and Calories
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a dewar flask is
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used to contain and store heat energy
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a thermocouple thermometer can be
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used to measure heat flow rate
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Resistance equals
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force divided by rate
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the two forms of resistance in mechanical systems are
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friction and drag
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equation for force of friction is
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f equals Force coefficient of friction
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the equation for drag resistance is
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force divided by velocity
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drag resistance
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results from disruption of airflow
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sliding friction
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must be overcome to start object in motion
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kinetic friction
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must be overcome to keep object moving
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static friction is always _______ than kinetic friction`
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greater
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friction can be reduced by
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applying lubricants
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resistance created by solid going through fluid is
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fluid resistance
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Laminar flow is the opposite of
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turbulent flow
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fluid resistance is proportional to
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pipe length
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formula for fluid resistance
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Rf =Dp/Qv
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electrical resistance can be found by
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Re=Dv/I
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what is symbol of resistance in electrical systems
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greek symbol omega
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electrical resistance results
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when electrons run into metal atoms
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Resistors are used to
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control amount of voltage in circuit
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Conductors are
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materials that permit free flow of electrons
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Inductors are
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materials that do not permit free flow of electrons
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semi-conductors are
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materials that allow some current to pass through
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resistivity is
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quality of material that describes how much it permits
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in a series circuit total resistance is found by
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adding resistance values in the circuit
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in a parallel circuit total resistance is found by
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Rtot=(R1R2)/(R1+R2)
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Thermal resistance is
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opposition to the flow of heat
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equation for thermal resistance
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Rt=DT/Qh
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Thermal conductivity is
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quality of material that describes how well it transmits heat
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R-value is
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the rating of material based on ability to resist heat
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one formula for calculating thermal resistances is
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Rt=I/kA
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energy is
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ability to do work
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energy is used
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to overcome resistance
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potential energy is
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stored energy
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formula for potential energy is
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Ep=force*height
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Gravitational potential energy is
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energy an object has because it has been raised against gravitational pull
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elastic potential energy is
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energy an object has because its shape has been temporarily changed
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spring constant equation is
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k=f/d
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potential energy stored inn a compressed spring is calculated by
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Ep=kd^2
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potential energy of water stored in tank is calculated by
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Ep=weight of water*height
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kinetic energy is
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energy of motion possessed by a moving body
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linear mechanical systems, kinetic energy is found by
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Ek=.5mv^2
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moment of inertia acts
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like mass in rotational systems
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total energy in a system
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is equal to sum of potential and kinetic energy
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electrical energy is
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potential and kinetic energy that are associated with position or movement of electrical charge
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capacitors are used
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to store electrical charge
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capacitance is measured in
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farads
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inductors are
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another way to store electrical energy
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inductance is measured in
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heneries
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thermal energy is connected to
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work
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heat is calculated by formula
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H=mcDT
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Mechanical equivalent of heat is
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mathematical quantity that equates a unit of heat in calories
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calories and Btu are
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units of energy
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latent heat is
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heat added or subtracted from substance during change of state
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conduction is
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movement of heat energy from warmer to cooler regions
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convection is
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transfer of heat by movement of a fluid medium
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radiation
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transfer of heat energy by electromagnetic raditation
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