Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
134 Cards in this Set
- Front
- Back
|
Force Equals...
|
Mass Times Acceleration
|
|
|
A force is a push or pull that causes changes in what?
|
Changes in shape or direction of movement
|
|
|
Definition of mass?
|
total amount of matter in an object as measured in grams in the SI system or pound-mass in the English system
|
|
|
How do you find weight?
|
Gravity times Mass
|
|
|
Torque is a force like quantity that is found in what kind of system?
|
Rotational mechanical systems
|
|
|
Net force is found when...
|
two forces act on the same object. The net force is the combination of the two.
|
|
|
Prime movers are what?
|
Force-like quantities that act in the same way as a force does in mechanical systems
|
|
|
Density formula?
|
Mass divided by Volume
|
|
|
A hydrometer is used to measure what?
|
Density or specific gravity in liquids
|
|
|
Units for pressure in SI and English systems?
|
English-p.s.i. or pounds per square inch
SI-grams per centimeter squared |
|
|
Manometers measure what?
|
Pressure differences.
|
|
|
What are the two types of fluids?
|
Pneumatic and Hydraulic
|
|
|
If gasses are compressible, then liquids are ____.
|
not compressible.
|
|
|
Pressure increases with ___ in a fluid.
|
Depth
|
|
|
Absolute pressure is measured in references with a vacuum, which is also called...
|
zero pressure
|
|
|
Weight density is the measure of an objects weight to its ___
|
volume
|
|
|
Voltage comes in what two forms?
|
AC and DC current.
|
|
|
Voltmeters measure voltage ___
|
differences
|
|
|
Multimeters measure what three things?
|
voltage, amperage, and resistance
|
|
|
Positive pole in a battery is called a ___.
Negative pole in a battery is called a ___. |
anode; cathode
|
|
|
Electrical circuits contain what?
|
a source, conductors, and a load. A switch is optional.
|
|
|
Temperature acts as the what in thermal systems?
|
The prime mover
|
|
|
Heat is a form of ___.
|
energy
|
|
|
Temperature is a measure of what?
|
Average energy of the motion of molecules in a substance.
|
|
|
Thermocouples measure what by using what?
|
Temperature using three wires of two different metals
|
|
|
When is the degree symbol placed after Celsius or Fahrenheit?
|
Only during a difference in temperature has taken place.
|
|
|
Work equals
|
force times distance
|
|
|
Input work is
|
the work going into a system
|
|
|
Output work
|
work coming out of a system
|
|
|
Efficiency definition and formula
|
How well the machine is outputting it's work. efficiency equals output over input work
|
|
|
Spring scales measure
|
input and output force
|
|
|
Work is found in a rotational system by doing what?
|
Torque times the angle (at which the lever arm moved)
|
|
|
Basic English unit of work?
|
Foot-Pound
|
|
|
Basic SI unit of work?
|
Newton-Meter
|
|
|
Linear mechanical work is performed when...
|
a mass is moved in a straight line.
|
|
|
Angular mechanical work is performed when...
|
a mass is moved around an axis or rotation
|
|
|
Mechanical work's definition
|
this causes an object to start moving, stop moving, or change direction.
|
|
|
Fluid work equals...
|
Pressure difference times the volume moved.
|
|
|
To calculate fluid work you must know what two things?
|
height and weight density of the fluid
|
|
|
In what liquid system is the fluid reused?
|
Closed
|
|
|
There is no such thing as ___ or ___ fluid work.
|
Linear; Rotational
|
|
|
How can you find the work done by a piston?
|
the pressure times the area of the piston face
|
|
|
The cross sectional area of a cylinder can be found by multiplying what number by the diameter squared?
|
0.7854
|
|
|
Electrical work is done when what?
|
A voltage moves a specific amount of electrical charge.
|
|
|
a coulomb is a quantity of electrical charge found by how many electrons?
|
6.25 times 10 ^18th
|
|
|
Electrical charge is calculated by what?
|
multiplying amperes by time
|
|
|
Basic unit of electrical work?
|
The joule
|
|
|
Input work by a pump or motor is given in what form?
|
joules
|
|
|
A rate is found by what?
|
Taking the displacement like quantity and dividing it by time
|
|
|
Velocity is the measure of what?
|
linear mechanical work.
|
|
|
Speed has only what one difference from velocity?
|
it is scalar (no directional rotation).
|
|
|
Units of linear mechanical rate are what in the English and SI systems?
|
English- Foot per second
SI- Meter per second |
|
|
Angular rate is expressed by what in the English and SI systems?
|
English- Radians per second
SI- Revolution per minute |
|
|
There are how many radians in one revolution?
|
6.28
|
|
|
A what measures angular rate?
|
stroboscope
|
|
|
Acceleration is the rate of what?
|
at which a speed increases or decreases.
|
|
|
How do you find flow rate?
|
Volume of fluid moved divided by the time
|
|
|
Units of flow rate in the English and SI systems?
|
English- gallons per minute
SI- cubic meters per second |
|
|
Viscosity is what?
|
The thickness of a substance
|
|
|
Under the same pressure, would a smaller or larger pipe have a higher flow rate?
|
larger
|
|
|
Electrical rate is what?
|
Amount of charge moved in a given period of time
|
|
|
Electrical rate is found by what?
|
charge moved divided by time
|
|
|
Electrical current flow is measured in what?
|
amperes
|
|
|
One milliampere equals what?
|
1/1000 amps
|
|
|
One microampere equals what?
|
.000001 amps
|
|
|
An ammeter measures what?
|
current
|
|
|
Hertz is the measure of what?
|
frequency in an alternating current
|
|
|
An oscilloscope can measure what?
|
frequency as well as voltage waveform.
|
|
|
Heat flow rate is symbolized by what?
|
Qh
|
|
|
Heat flow rate is what?
|
amount of heat energy transferred through a substance in a unit of time.
|
|
|
Units of heat are what in the English and SI systems?
|
English- BTU
SI- kilocalorie |
|
|
A dewar flask is used for what?
|
to contain and store heat energy
|
|
|
A thermocouple can measure what?
|
Heat flow rate.
|
|
|
What is the unifying equation for resistance?
|
Force like quantity devided by a rate
|
|
|
Two kinds of resistance in mechanical systems?
|
Friction and drag.
|
|
|
Friction equals...
|
Force times the coefficient of friction
|
|
|
Drag is what?
|
Disruption of air flow as an object moves. Called turbulance
|
|
|
Sliding friction must be overcome to...
|
put an object in motion
|
|
|
Kinetic friction must be overcome to...
|
keep an object in motion
|
|
|
Static friction is always greater that what?
|
Kinetic friction
|
|
|
Friction can be reduced by what?
|
Adding lubricants
|
|
|
Resistance caused by a solid moving through a liquid is called what?
|
Fluid resistance
|
|
|
Laminar flow is opposite of what?
|
Turbulent flow
|
|
|
Fluid resistance is proportional to what?
|
Length of the pipe.
|
|
|
Formula for fluid resistance is (using letters)...
|
Rf=Dp/Qv
|
|
|
Electrical resistance equals what?
|
voltage difference divided by electrical current flow.
|
|
|
What are resistors used for?
|
Used to control the amount of voltage in a circuit
|
|
|
Conductors do what?
|
Permit the free flow of electrons.
|
|
|
Insulators do what?
|
Do not permit the free flow of electrons.
|
|
|
Semi-conductors do what?
|
Allow some flow of electrons.
|
|
|
Resistivity definition?
|
Describes how much electricity can flow through it.
|
|
|
How do you find the total resistance in a series circuit?
|
Add all the resistance values in the circuit.
|
|
|
Formula for resistance in a parallel circuit?
|
Rtot=(R1R2)/(R1+R2)
|
|
|
Thermal resistance is...
|
opposition of heat flow
|
|
|
Equation for thermal resistance?
|
Rtot = DT/Qh
|
|
|
Thermal conductivity is...
|
The quality of a material that describes how well it transmits heat
|
|
|
What is an R-Value (or R-Factor)?
|
Rating of a material based on its ability to resist heat flow.
|
|
|
Formula for calculating thermal resistance?
|
Rt=l/ka
|
|
|
Energy is what?
|
The ability to do work
|
|
|
Energy is used to what?
|
Overcome resistance in a system
|
|
|
Potential energy is what?
|
Energy stored in a mechanical, fluid, or electrical device by virtue of a change in shape or position
|
|
|
Formula for potential energy is what?
|
Potential energy equals Force times height
|
|
|
Gravitational potential energy is...
|
energy that an object has because it is raised against the gravitational pull of the earth.
|
|
|
Elastic potential energy is...
|
Energy an object has stored due to a temporary change in shape.
|
|
|
A spring constant is found by what?
|
Force required to stretch the spring divided by the distance the spring is stretched
|
|
|
Potential energy stored in a compressed spring is found by what formula?
|
Ep=kd^2
|
|
|
Potential energy of a water tank is found by..
|
weight of water times its height off the ground.
|
|
|
Kinetic energy is possessed by what type of body?
|
a moving one
|
|
|
Kinetic energy in a linear mechanical system is found by what formula?
|
Ek=1/2mv^2
|
|
|
Moment of inertia is what?
|
Quantity that acts like a mass in rotational mechanical systems.
|
|
|
Total energy in a system is found by adding what two things?
|
potential and kinetic energy.
|
|
|
Electrical energy is what?
|
The potential energy and kinetic energy that are associated with the position or movement of electrical charge.
|
|
|
Capacitors do what?
|
Stores electrical charge, therefore, stores electrical potential energy.
|
|
|
Capacitance is measured in what? Found by what formula?
|
Farads; C=q/V
|
|
|
Inductors are what?
|
Electronic devices that consist of a coil of wire wrapped around a core. They store electrical energy and they oppose current changes
|
|
|
Inductance is measured in what?
Found by what formula? |
Henries; Ep=1/2LI
|
|
|
Thermal energy is connected to work because...
|
When work is done, energy is lost in the form of heat. This is why efficiency is always less than 100%
|
|
|
Heat is found by what formula?
|
H=mcDT
|
|
|
Mechanical Equivalent of Heat is what?
|
a mathematical quantity that equates a unit of heat in calories or Btu to the same amount of energy in mechanical units of joules of foot-pounds. Mechanical equivalent of heat equals the mechanical energy expended divided by the heat energy produced when all mechanical energy goes into heat energy
|
|
|
What are the two units of energy?
|
Calories and btu
|
|
|
Latent heat information
|
Heat that is added to or subtracted from a substance during a change of state from a solid or liquid or vice versa. This means that heat energy used is not given off as sensible heat because it is used in the change of state.
|
|
|
Conduction is...
|
the movement of heat energy from warmer to colder regions by the direct transfer of molecular vibration from molecule to molecule
|
|
|
Convection is...
|
The transfer of heat energy by movement of a fluid from one region to another.
|
|
|
Radiation is what?
|
Transfer of heat energy by electromagnetic radiation
|
|
|
Power is the rate of what?
|
Doing work.
|
|
|
Unifying equation for power?
|
P=work/time
|
|
|
Power is measured in what?
|
English- foot-pounds/seconds or horsepower
SI- watts |
|
|
One watt is equal to what?
|
one joule per second
|
|
|
one horsepower is equal to how many foot-pounds/second?
|
550
|
|
|
one horsepower is equal to how many watts?
|
746
|
|
|
The kilowatt-hour is a measure of what?
|
Energy, not power because the time units cancel each other
|
|
|
What ways can you express a watt?
|
One volt times one amp or power equals one volt times one coulomb divided by one second
|
|
|
in rotational mechanical systems, power equals what?
|
torque times angular rate
|
|
|
in fluid systems, power equals what?
|
pressure difference times flow rate
|
