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Rpm
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 defines a physical quantity called ''rotation'' (or ''number of revolutions''), dimensionless, whose instantaneous rate of change is called ''rotational frequency'' (or ''rate of rotation''), with units of reciprocal seconds (s−1). A related but distinct quantity for describing rotation is ''angular frequency'' (or ''angular speed'', the magnitude of angular velocity), for which the SI unit is the radian per second (rad/s). Although they have the same dimensions (reciprocal time) and base unit (s−1), the hertz (Hz) and radians per second (rad/s) are special names used to express two different but proportional ISQ quantities: frequency and angular frequency, respectively. The conversions between a frequency and an angular frequency a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonograph Record
A phonograph record (also known as a gramophone record, especially in British English) or a vinyl record (for later varieties only) is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts near the outside edge and ends near the center of the disc. The stored sound information is made audible by playing the record on a phonograph (or "gramophone", "turntable", or "record player"). Records have been produced in different formats with playing times ranging from a few minutes to around 30 minutes per side. For about half a century, the discs were commonly made from shellac and these records typically ran at a rotational speed of 78 rpm, giving it the nickname "78s" ("seventy-eights"). After the 1940s, "vinyl" records made from polyvinyl chloride (PVC) became standard replacing the old 78s and remain so to this day; they have since been produced in various sizes and speeds, most commonly 7-inch discs pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Drill
A dental drill or dental handpiece is a hand-held, mechanical instrument used to perform a variety of common dentistry, dental procedures, including removing tooth decay, decay, polishing dental filling, fillings, performing cosmetic dentistry, and altering Dental prosthesis, prostheses. The handpiece itself consists of internal mechanical components that initiate a rotational force and provide power to the cutting instrument, usually a dental burr. The type of apparatus used clinically will vary depending on the required function dictated by the dental procedure. It is common for a light source and water cooling, cooling water-spray system to also be incorporated into certain handpieces; this improves visibility, accuracy, and the overall success of the procedure. The burrs are usually made of tungsten carbide or diamond. High-speed handpiece Depending on their mechanisms, handpieces are classified as air turbine or electric (including speed-increasing). However, in a clinical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Frequency
Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). Rotational frequency can be obtained dividing ''angular frequency'', ω, by a full turn (2 π radians): ''ν''ω/(2πrad). It can also be formulated as the instantaneous rate of change of the number of rotations, ''N'', with respect to time, ''t'': ''n''d''N''/d''t'' (as per International System of Quantities). (11 pages) Similar to ordinary period (physics), per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. The interval of time between events is called the period. It is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), its period is one half of a second. Special definitions of frequency are used in certain contexts, such as the angular frequency in rotational or cyclical properties, when the rate of angular progress is measured. Spatial frequency is defined for properties that vary or cccur repeatedly in geometry or space. The unit of measurement of frequency in the International System of Units (SI) is the hertz, having the symbol Hz. Definitions and units For cyclical phenomena such as oscillations, waves, or for examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Speed
Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). Rotational frequency can be obtained dividing ''angular frequency'', ω, by a full turn (2 π radians): ''ν''ω/(2πrad). It can also be formulated as the instantaneous rate of change of the number of rotations, ''N'', with respect to time, ''t'': ''n''d''N''/d''t'' (as per International System of Quantities). (11 pages) Similar to ordinary period (physics), period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radian Per Second
The radian per second (symbol: rad⋅s−1 or rad/s) is the unit of angular velocity in the International System of Units (SI). The radian per second is also the SI unit of angular frequency (symbol ''ω'', omega). The radian per second is defined as the angular frequency that results in the angular displacement increasing by one radian every second. Relation to other units A frequency of one hertz (1 Hz), or one cycle per second (1 cps), corresponds to an angular frequency of 2 radians per second. This is because one cycle of rotation corresponds to an angular rotation of 2 radians. Since the radian is a dimensionless unit in the SI, the radian per second is dimensionally equivalent to the hertz—both can be expressed as reciprocal seconds, s−1. So, context is necessary to specify which kind of quantity is being expressed, angular frequency or ordinary frequency. One radian per second also corresponds to about 9.55 revolutions per minute (rpm). ''Degrees pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engine
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power generation), heat energy (e.g. geothermal), chemical energy, electric potential and nuclear energy (from nuclear fission or nuclear fusion). Many of these processes generate heat as an intermediate energy form; thus heat engines have special importance. Some natural processes, such as atmospheric convection cells convert environmental heat into motion (e.g. in the form of rising air currents). Mechanical energy is of particular importance in transportation, but also plays a role in many industrial processes such as cutting, grinding, crushing, and mixing. Mechanical heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a mechanical heat engine in wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation (quantity)
The turn (symbol tr or pla) is a unit of plane angle measurement that is the measure of a complete angle—the angle Subtended angle, subtended by a complete circle at its center. One turn is equal to radians, 360 degree (angle), degrees or 400 gradians. As an angular unit, one turn also corresponds to one cycle (symbol cyc or c) or to one revolution (symbol rev or r). Common related Frequency#Unit, units of frequency are ''cycles per second'' (cps) and ''revolutions per minute'' (rpm). The angular unit of the turn is useful in connection with, among other things, electromagnetic coils (e.g., transformers), rotating objects, and the winding number of curves. Divisions of a turn include the half-turn and quarter-turn, spanning a Angle#Individual angles, straight angle and a right angle, respectively; metric prefixes can also be used as in, e.g., centiturns (ctr), milliturns (mtr), etc. In the International System of Quantities, ISQ, an arbitrary "number of turns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washing Machine
A washing machine (laundry machine, clothes washer, washer, or simply wash) is a machine designed to laundry, launder clothing. The term is mostly applied to machines that use water. Other ways of doing laundry include dry cleaning (which uses alternative cleaning fluids and is performed by specialist businesses) and ultrasonic cleaning. Modern-day home appliances use electric power to automatically clean clothes. The user adds laundry detergent, which is sold in liquid, powder, or dehydrated sheet form, to the wash water. The machines are also found in commercial laundromats where customers pay-per-use. History Washing by hand Laundering by hand involves soaking, beating, scrubbing, and rinsing dirty textiles. Before indoor plumbing, it was necessary to carry all the water used for washing, boiling, and rinsing the laundry from a pump, Water well, well, or Spring (hydrology), spring. Water for the laundry would be hand-carried, heated on a fire for washing, and then poured i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reciprocal Second
The inverse second or reciprocal second (s−1), also called ''per second'', is a unit defined as the multiplicative inverse of the second (a unit of time). It is applicable for physical quantities of dimension reciprocal time, such as frequency and strain rate. It is dimensionally equivalent to: * hertz (Hz), historically known as cycles per second – the SI unit for frequency and rotational frequency * becquerel (Bq) – the SI unit for the rate of occurrence of aperiodic or stochastic radionuclide events * baud (Bd) – the unit for symbol rate over a communication link * bit per second (bit/s) – the unit of bit rate However, the special names and symbols above for s−1 are recommend for clarity. Reciprocal second should not be confused with radian per second (rad⋅s−1), the SI unit for angular frequency and angular velocity. As the radian is a dimensionless unit, radian per second is dimensionally consistent with reciprocal second. However, they are used for d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
