In metric system, fundamental mass units {mass measurement} are gram {gram} (g) or kilogram {kilogram, mass unit} (kg). A derived mass measure is 1000 kilograms {tonne}. Atom mass unit is 10^-24 grams {atomic mass unit}, 1/12 of carbon-12 atom mass. Mass unit in English units is slug {slug, mass}.
Mass, in kilograms, times acceleration, in meters per second squared, is force unit {force measurement} in newtons (N), in MKS system. Mass, in grams, times acceleration, in centimeters per second squared, is force unit {dyne} in CGS system.
Mass times gravity acceleration is weight. In English measure, weight measurements use different systems, depending on mass range.
avoirdupois
In avoirdupois units {avoirdupois}, 28.35 grams is 1 ounce {avoirdupois ounce}. Avoirdupois weights include 16 avoirdupois ounces {avoirdupois pound} {pound, weight}, 100 avoirdupois pounds {hundredweight}, 2000 avoirdupois pounds {ton, weight}, 1/16 avoirdupois ounces {dram}, 1/7000 avoirdupois pounds {grain, mass unit}, 100 avoirdupois pounds {cental}, 100 avoirdupois pounds or 112 avoirdupois pounds or 100 kilograms {quintal}, and 2240 avoirdupois pounds {long ton}.
apothecary
Apothecary weights {apothecaries measure} depend on 1 grain {apothecary grain}. Apothecary weights include 20 apothecary grains {apothecary scruple}, 3 apothecary scruples {apothecary dram}, 8 apothecary drams {apothecary ounce}, 12 apothecary ounces {apothecary pound}. Apothecary pound has same weight as troy pound.
troy
Troy weights, based on 1 grain {troy grain}, are for weighing gold, silver, and jewels. Troy weights include 24 troy grains {troy pennyweight}, 20 troy pennyweight {troy ounce}, and 12 troy ounce {troy pound}.
electromagnetism
Electric force is in newtons. Magnetic force has units {unit pole}.
Force, in newtons, times distance, in meters, is work and energy {energy measurement} in joules (J), in MKS system. Force, in dynes, times distance, in centimeters, is energy unit {erg} in CGS system. 10000 erg equals 1 joule.
In English measure, force is weight, in pounds, times distance, in feet {foot-pound}.
electric
Voltage, in volts, times charge, in coulombs, is electric energy in joules. For subatomic particles, electric energy is voltage, in volts, times electron charge {electron-volt} (eV). Electric energy is power, in kilowatts, times time, in hours {kilowatt-hour}. USA houses use hundreds of kilowatts each month.
heat
Heat energy is energy needed to heat one gram of water one degree Celsius {calorie} (cal) or one kilogram of water one degree Celsius {Calorie} (Cal). 1 Cal = 1000 cal. In English measure, heat energy uses larger units {British thermal unit} (BTU).
Temperature units {temperature measurement} relate to water freezing and boiling temperatures. In Kelvin (K), freezing point is 273 degrees and boiling temperature is 373 degrees. In Celsius (C), freezing point is 0 degrees and boiling temperature is 100 degrees. In English measure {Fahrenheit} (F), freezing point is 32 degrees and boiling temperature is 212 degrees. An English temperature measure {Rankine} is Fahrenheit plus 459.69 degrees.
Force, in dynes, times time, in seconds {dyne-second}, is impulse, impact, or action {impulse measurement}.
In SI system, power per area {intensity measurement} can be power per steradian. Informally, intensity is flux per steradian, pressure divided by time, or force per second per unit distance.
Sound intensity uses logarithmic scale {bel}, or its tenths {decibel} (db) (dB), so 10 db equals 1 bel. Whispers are 30 db. Siren loudness is 100 dB. Larger units {neper} are 6.686 db.
Light intensity compares to standard candle {candela, intensity} (cd) {international candle} {candle, light} {lumen, light}. One candela is light intensity 1/683 watts per steradian, at frequency 540 * 10^12 hertz.
Energy, in joules, divided by time, in seconds, is power {power measurement} in watts (W). In refrigeration, 3517 watts are one ton {ton, refrigeration}. In English measure, power compares to standard horse power {horsepower}.
Mixing alkanes and benzenes makes gasoline {gasoline measurement}, which has engine power {octane number}. Octane is 87 for regular gas, 89 for intermediate gas and 91 for premium gas.
Force, in newtons, divided by area, in square meters, is pressure {pressure measurement} in pascals. Atmospheric pressure has pressure units {bar, pressure unit} {atmosphere, pressure unit} (atm). Pressure is how high mercury rises in columns {torr} {mm Hg} {inches Hg}. 1 atm equals 760 mm Hg. Standard temperature and pressure (STP) is 25 C and 1 atm. In English measure, pressure is force, in pounds, divided by area, in square inches {pounds per square inch} (psi).
Mass, in grams, divided by volume, in cubic centimeters, is density {density measurement}: d = g/cm^3. Water density is 1 g/cm^3.
Metals {gold measurement} can have purity {karat} (K). 28 K is pure. 24 K is high purity. 18 K is good purity. 14 K is strong. 10 K is strongest.
Dynamic-viscosity unit {poise, viscosity unit} differs from kinetic-viscosity unit {myriastoke} {viscosity measurement}.
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Date Modified: 2022.0225