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90 Cards in this Set
- Front
- Back
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Force=?
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mass x acceleration
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a force is a ______
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push or pull that causes a change in shape or a change in motion
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mass is the __________
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total amount of matter in an object, measured in grams(SI) or pound-mass (English)
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weight?
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is the measurement of gravity times mass
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torque?
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is the force-like quantity in rotational mechanical systems
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net force?
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when forces act in the same direction the net force is the sum of the two forces. when forces act in opposite directions the net force is the difference of the forces
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Prime Movers:
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pressure difference (fluid systems), voltage (electrical systems), and tempurature difference (thermal systems)
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density?
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is found by dividing mass by volume
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a hydrometer is _______
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used to measure density and specific gravity in liquids
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pressure?
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is found by dividing a unit of force by a unit of area
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manometers are
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used to measure pressure differences
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the two types of fluid are________
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hydraulic (using liquid) and pnuematic (using gas)
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gasses are _______
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compressible, liquids are not compressible
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pressure increases......
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with depth in a fluid but is independent of volume
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absolute pressure is.......
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measured in referance to a vacume (zero pressure). gage pressure is measured relative to atomspheric pressure. gage pressure + atmospheric pressure= total pressure
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weight density?
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is the ratio of an objects weight to its volume
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voltage....
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comes in two forms, direct current (DC) and alternating current (AC)
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voltmeters....
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measure voltsge difference
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multimeters....
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mearsure voltage, amperage, and resistance (in ohms)
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the positive pole.....
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is an anode. the negitve pole is the cathode
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electrical circuits....
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contain a source, conductors, a load, and a control element
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temperature difference......
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acts as the prime mover in thermal systems because heat always moves from warmer to cooler reigons
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heat.....
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is a form of energy characterized by the vibrating movment of atoms and molecules
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temperature...
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is the measure of the average energy of motion in a substance
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thermocouples...
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use three wires of two different metals to measure temperature
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the degree symbol.....
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is placed in front of F and C when giving the tempersture and behind the F and C when givin the temperature difference
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work=
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force (or force-like quantity) times distance (or displacment-like quantity)
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input work....
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is the work going into a system, performed by a human or a motor
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output work...
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is the work done by the system
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efficiency....
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is the output work didved by input work, multiplied by 100. efficiency can not exceed 100%
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spring scales....
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are used to measure input and output force
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in a rotational mechanical system.....
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work is equal to torque multiplied by the angle that the lever arm moves through
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the basic english unit for work...
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foot-pound
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the basic SI unit for work....
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newton-meter
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linear mechanical work...
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is performed when a mass is moved in a straight line
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angular mechanical work....
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is performed when a mass is moved around an axis or rotation
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mechanical work....
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causes an object to start moving, stop moving, or change direction
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fluid work...
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is equal to the pressure difference times the volume moved (W=Dp x V)
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when given the height that a fluid is raised....
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you must also know the weight density of the fluid in order to calculate fluid work
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in a closed fluid system...
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the fluid is resused
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is there any such thing as linear or angular fluid work?
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no
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the pressure s exerted by...
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a piston multiplied by the area of the piston face equals the work done by the piston
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the cross-sectional area of a cylinder...
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can be found by multiplying 0.7854 by the diameter squared
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electrical work...
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is done when a voltage moves a specified amount of charge (EW=V x q)
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a coulomb...
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is a quantity of charge equal to 6.25 x 10^18 electrons
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electrical charge can be calculated by....
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multiplying amperes by time
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the basic unit for electrical work...
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is the joule (joule= 1 volt x coulomb)
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input work performed by an electrical pump or motor.....
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will be given in joules
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a rate is...
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a displacement-like quantity divided by elapsed time
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velocity...
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is the measure of linear mechanical work
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speed...
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is similar to velocity, but it has no scalar (no directional notation)
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units of linear mechanical rate are.....
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the foot per second (English) and the meter per second (SI)
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angular rate...
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is expressed in radians per second (SI) or revolutions per minute (English)
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there are 6.28 radians...
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in one revolution (360 degrees)
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a stroboscope...
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is used to measure angular rate
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acceleration...
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is the rate at which speed increases or decreases
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in fluid systems, flow rate
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is the volume of fluid moved in a given period of time (Qv)
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units of fluid flow are...
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gallons/minute (English), cubic feet/second (English), and cubic meter/second (SI)
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viscosity...
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is the quality of a substance related to its thickness
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under the same pressure, a larger pipe...
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will have a higher flow rate than a smaller pipe
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electrical rate...
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is the amount of charge moved (in coulombs) in a given period of time
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electrical current flow...
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is symbolized by an "I" and is measured in amperes
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one milliampere...
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is equal to 1/1000 amps
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one microampere....
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is equal to 1 x 10^-6 amps
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an ammeter....
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is used to measure current
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hertz....
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is a measure of frequency in an alternating current
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an oscilloscope...
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can measure frequency as well as voltage waveform
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heat flow rate...
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is symbolized by a Qh
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heat flow rate is...
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the 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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the BTU (English) and the calorie (SI)
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a dewar flask....
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is used to contain and store heat energy
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a thermocouple.....
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can be used to measure heat flow rate
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the unifying equation for resistance...
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resistance equals a force-like quantity divided by a rate
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the two forms of resistance in a mechanical system...
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are friction and drag
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the equation for the force of friction...
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f equals force times coefficient of friction
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the equation for drag resistance....
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resistance equals force divided by velocity
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drag resistance results from...
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the disruption of airflow as an object moves
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sliding friction....
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must be overcome to start an object in motion
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kinetic friction...
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must be overcome to keep an object in motion
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static friction is...
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always greater than kinetic friction
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friction...
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can be reduced by the addition of lubricants
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fluid resistance...
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resistance generated by a solid object moving through a fluid
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laminar flow...
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is the opposite of turbulent flow. in laminar flow, the fluid moves around the object in layers
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fluid resistance when transporting a liquid...
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by heating the liquid. fluid resistance is also proportional to the length of the pipe
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the formula for fluid resistance...
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Rf= Dp/Qv
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electrical resistance...
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is equal to voltage difference divided by electrical current flow
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ohms law...
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is the standard equation for calculating electrical resistance
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electrical resistance results when...
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electrons run into metal atoms inside wires
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resistors...
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are used to control the amount of voltage in a circuit
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conductors..
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metals such as copper and solder that permit the free flow of electrons
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