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119 Cards in this Set
- Front
- Back
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Force Equals?
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Mass times acceleration
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What is a push or pull that causes a change in shape or a change in motion?
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Force
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What is the total amount of matter in an object, as measured is grams (SI)or pounds mass (english)
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Mass
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what is the force- like quantity in rotational mechanical systems?
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Torque
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what is the sum of two forces when forces act in the same direction.
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Net force
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What are prime-movers?
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In fluid, electrical, and thermal systems there are force-like quantities that act in the same way as a force does in mechanical.
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What is found by dividing mass by volume?
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Density
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What is used to measure density or specific gravity in fluids?
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Hydrometer
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What is measured by dividing a unit of force by a unit of area?
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Pressure
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What are used to measure pressure differences?
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Manometers
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What are two types of fluid?
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Hydraulic and pneumatic
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True or false? Gasses are compressible, liquids are not compressible?
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True
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what increases with depth in a fluid but is independent of volume?
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Pressure
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What is measured in reference to a vacuum (zero pressure)?
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Absolute pressure
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what is the ratio of an object's weight to its volume?
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Weight Density
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What comes in two forms, direct current and alternating current?
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Voltage
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what measures volt difference?
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voltmeters
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What measure voltage, amperage, and resistance?
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Multimeters
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What are the positive and negative electrodes on a battery called?
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Positive: anode Negative: cathode
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what contain a source (battery or AC power supply)
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Electrical circuits
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What acts as a prime mover in thermal systems because heat always moves from warmer to cooler regions?
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temperature difference
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What is a form of energy characterized by the vibrating movement of atoms and molecules?
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Heat
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What is the measure of the average energy of motion of molecules in a substance?
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Temperature
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What use three wires of two different metals to measure temperature?
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Thermocouples
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Where is the degree symbol placed when giving temperature difference?
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After the F or C
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What equals force times distance?
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Work
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What is the work going into a system, performed by a human or motor?
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Input work
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What is work done by the system?
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Output Work
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What are used to measure input and output force?
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Spring Scales
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True or false: in rotational mechanical systems, work is equal to torque multiplied by the angle through which the lever arm moves.
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True
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What is the basic English unit of work
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Foot-Pounds
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What is the basic SI unit of work?
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Newton-meter
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What is performed when mass is moved in a straight line?
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Linear mechanical work
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What is performed when a mass is moved around an axis or rotation?
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Angular mechanical work
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What is equal to the pressure difference times the volume moved?
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Fluid work
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what must you know to calculate fluid work?
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Weight Density
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True or False: in a fluid system such as a hydraulic brake system the fluid is reused.
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True
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True or false: there is no such thing as linear or angular fluid work.
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True
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The pressure exerted by a piston multiplied by the area of the piston face equals what?
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Work done by the piston
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The cross-sectional area of a cylinder can be found by?
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multiplying 0.7854 by the diameter
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what is done when a voltage move a specified amount of electrical charge?
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Electrical work
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what is a quantity of charge equal to 6.25 times 10^18 electrons?
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A coulomb
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What can be calculated by multiplying amperes by time, since the time units will cancel, leaving only the amount of charge?
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Electrical charge
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What is the basic unit of electrical work?
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joule
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What will input work performed by and electrical pump or motor be given in?
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Joules
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What is a displacement-like quantity divided by elapsed time.
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Rate
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What is the measure of linear mechanical work?
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Velocity
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What is similar to velocity, but it is scalar?
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Speed
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What are the english and SI units of linear mechanical rate?
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English- foot per second (SI) meter per second
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how many radians are there in one revolution?
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6.28
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what is used to measure angular rate?
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Stroboscope
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What is the rate at which speed increases or decreases
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Acceleration
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What is the volume of fluid moved in a given period of time?
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Flow rate
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What is the quality of a substance related to its thickness?
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Viscosity
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True or false: under the same pressure, a larger pipe will have a higher flow rate than a smaller pipe?
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True
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What is the amount of charge moved in a given period of time?
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Electrical rate''''
Electrical rate |
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What is electrical flow measured in?
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Amperes
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What is one milliampere equal to?
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1/1000 amps (or .001)
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What is one microampere equal to?
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.000001 amps
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What is used to measure current?
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ammeter
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what is a measure of frequency in alternating current
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hertz
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what can measure frequency as well as voltage wave form?
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oscilloscope
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What is heat flow rate symbolized by?
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Q^H
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what is used to contain and store heat energy?
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A Dewar flask
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what are two metals commonly used in thermocouples?
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Constantan and Cromel
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what is the unifying equation for resistance?
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Resistance equals a foce-like quantity divided by a rate
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what are the two forms of resistance in a mechanical system?
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Friction and drag
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what will usually be a weight that that is being moved across a surface?
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Force
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what is the equation for drag resistance?
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resistance equals force divided by velocity
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what results from the disruption of airflow as an object moves?
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Drag resistance
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what is a disruption in flow?
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turbulence?
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what is the most streamlined shape?
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Teardrop
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What type of friction must be overcome to start an object in motion?
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Sliding friction
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What can you add to reduce friction?
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Lubricants
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what is resistance generated by a solid moving through a fluid?
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Fluid resistance
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What is the opposite of turbulent flow?
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Laminar flow
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True or false: fluid resistance is also proportional to the length of the pipe
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True
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What is the formula for electrical resistance?
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Electrical resistance is equal to voltage difference divided by electrical current flow.
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What is ohm's law?
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the standard equation for calculating electrical resistance
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What causes electrical resistance?
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When electrons run into metal atoms inside wires.
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What are resistors?
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They are used to control the amount of voltage in a circuit.
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What are conductors?
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Materials such as copper and solder that permit the free flow of electrons.
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What are insulators?
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materials such as plastic and ceramic that do not permit the free flow of electrons.
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What are semi-conductors?
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materials, such as silicon, that allow some current to pass through.
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what is resistivity?
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the wuality of a material the describes how much it permits electricity to flow through it.
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how is total resistance found in a series circuit?
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it is found by adding the resistance values in the circuit.
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What is thermal resistance?
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opposition to the flow of heat through a material.
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what is thermal conductivity?
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the quality of a material that describes how well it transmits heat.
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What is R-value?
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the rating of material based on its ability ot resist heat flow
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What is enery?
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the ability to do work
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True or false: energy is used to overcome resistance in a system is lost in the form of heat
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True
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What is potential energy
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energy stored in a mechanical, fluid, or electrical device by virtue of change in shape or position.
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what is the formula for potential energy?
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Potential energy equals force times hieght.
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What is gravotational energy?
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energy that an object has because it has been raised against the gravotaional pull of earth.
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What is elastic potential energy?
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energy that an object has because its shpae has been temporarily changed.
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What is kenetic energy?
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the energy of motion possed by a moving body.
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what is the moment of inertia?
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the quantity that acts like mass in rotational mechanical systems.
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what is total energy in a system?
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equal to the sum of the potential energy and kenetic energy
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What is electrical energy?
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the potential energy and kenetic energy that are ossociated with the position or movement of electrical charge.
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What are capacitors?
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electronic devices consisting of conductors seperated by insulators.
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What is capacitance?
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measured in farands
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What are inductors?
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electronic devices that consist of a coil of wire wraped around a core.
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What is inductance measured in?
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henries
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Why is thermal energy connected to work?
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Because when work is done energy is lost in the form of hear.
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What is the mechanical equivalent of heat?
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a mathmatical quantity that equates a unit of heat in calories or btu to the same amount of energy in mechanical units of joules or foot-pounds
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Are calories and Btu units of energy?
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yes
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What is latent heat?
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heat that is added to or subtracted from a substance during a change of state from solid or liquid or liquid to solid.
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What is conduction?
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The movement of heat energy from warmer reagions to cooler regions by the direct transfer of molecular vibration from molecule to molecule.
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What is convection?
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the transfer of heat energy by movement of a fluid medium from one region to another.
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What is radiation?
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The transfer of heat energy by eloctromagnetic radiation
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What is power?
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the rate of doing work
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what is the equation for power?
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Power equals work diveded by time
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What is a watt?
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equal to one joule per second
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What is horsepower?
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550 footpounds per second
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what does one horsepower equal?
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746 watts
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What is kilowatt-hour a unit of power and not energy?
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because the time units cancel each other.
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True or false: in electrical systems one watt equals one volt times one amp
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True
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What does power equal in rotational mechanical systems?
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torque times angular rate
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What does power equal in fluid systems?
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Pressure difference times flow rate.
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