Menu Distance Conversion
Equals
Important Notes
- The base unit in the International System of Units (SI) is the meter defined as "the length of the path travelled by light in vacuum during a time interval of 1⁄299792458 seconds". It is approximately equal to 1.0936 yd.
- The basic unit of length in the Imperial and U.S. customary systems is the yard defined as exactly 0.9144 m. Common Imperial units and U.S. customary units of length include inch, foot, yard, mile, etc.
- In addition, fathom (for depth; only in non-metric countries) (2 yards=1.8288 m) and nautical mile (one minute of arc of latitude=1852 m) are the units frequently used by sailors.
- Meanwhile, Surveyors in the United States continue to use: chain (22 yards, or 20.1168 m) and rod (also called pole or perch) (quarter of a chain, or 5.0292 m)
- Astronomical measure uses: Astronomical unit [AU] ≈ 149597870700 m (approximately the distance between the Earth and Sun), light-year [ly] ≈ 9460730472580.8 km (the distance that light travels in a vacuum in one Julian year), etc.
Speed Conversion
Equals
Important Notes
- The SI unit of speed is the meter per second, but the most common unit of speed in everyday usage, is the kilometer per hour or, in the US and the UK, miles per hour. For air and marine travel the knot is commonly used.
- The most common way to calculate the speed of a moving object, the following formula is used: [ (distance moved by the object) / (time taken by object to complete the movement)]
- Speed can be thought of as rate at which an object covers distance. A fast-moving object has a high speed & covers a large distance in a given amount of time, while a slow-moving object covers a relatively small amount of distance in the same amount of time.
- The knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h (approximately 1.15078 mph or 0.514 m/s). The ISO standard symbol for the knot is kn.
- The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c=299792458 meters per second (approximately 1079000000 km/h or 671000000 mph).
Time Conversion
Equals
Important Notes
- A minute (min) is 60 seconds in length and an hour is 60 minutes or 3600 seconds in length. A day is usually 24 hours or 86,400 seconds in length; however, the duration of a calendar day can vary due to Daylight saving time and Leap seconds.
- A week includes 7 days, fortnight has 14 days and subdivisions of the day include the hour (1/24 of a day), which was further subdivided into minutes and finally seconds.
- A year is the time for the earth to revolve around the sun. Year-based units include the olympiad (4 years), the lustrum (5 years), the indiction (15 years), the decade, the century and the millennium.
- Planck time (which is equal to 5.39×10−44 s) is the time light takes to travel one Planck length. Theoretically, this is the smallest time measurement that will ever be possible.
- The Svedberg is a time unit used for sedimentation rates (usually of proteins). It is defined as 10−13 seconds (100 fs). Also, the galactic year is based on the rotation of the galaxy and usually measured in million years.
Area Conversion
Equals
Important Notes
- The SI unit of area is the square meter which is considered an SI derived unit.
- A shape with an area of three square meters would have the same area as three such squares. In mathematics, the unit square is defined to have area one and the area of any other shape or surface is a dimensionless real number.
- Every unit of length has a corresponding unit of area, namely the area of a square with the given side length. Thus, areas can be measured in square meters (m2), square centimeters (cm2), square millimeters (mm2), square kilometers (km2), square feet (ft2), square yards (yd2), square miles (mi2) and so forth.
- For a solid shape such as a sphere, cone or cylinder, the area of its boundary surface is called the surface area. The surface area of a solid object is a measure of the total area that the surface of the object occupies.
- Area plays an important role in modern mathematics. In addition to its obvious importance in geometry and calculus, area is related to the definition of determinants in linear algebra and is a basic property of surfaces in differential geometry.
Volume Conversion
Equals
Important Notes
- In the International System of Units (SI), the standard unit of volume is the cubic meter (m3). A cubic centimeter (cm3) is the volume of a cube whose sides are one centimeter (1 cm) in length.
- The metric system also includes the litre (L) as a unit of volume where one litre is the volume of a 10-centimeter cube.
- The gallon is a unit of measurement for volume and fluid capacity in both the US customary units and the British imperial systems of measurement. 1 US fluid gallon is equal to 3.785411784 liters and 1 imperial gallon is equal to 4.54609 liters.
- A barrel is one of several units of volume applied in various contexts; there are dry barrels, fluid barrels (such as the U.K. beer barrel and U.S. beer barrel), oil barrels and so forth.
- Various other traditional units of volume are also in use, including the cubic inch, the cubic foot, the cubic yard, the cubic mile, the teaspoon, the tablespoon, the fluid ounce, the fluid dram, the gill, the pint, the quart, the minim, the cord, the peck, the bushel, the hogshead, the acre-foot and the board foot.
Mass Conversion
Equals
Important Notes
- The standard International System of Units (SI) unit of mass is the kilogram (kg). The kilogram is 1000 grams (g) and the tonne (t) (or "metric ton") is equal to 1000 kg.
- The pound (lb) is a unit of both mass and force, used mainly in the United States (about 0.45 kg or 4.5 N). In scientific contexts where pound (force) and pound (mass) need to be distinguished, SI units are usually used instead.
- The slug (sl) is an Imperial unit of mass of 32.1740 lb (about 14.6 kg) based on standard gravity.
- The electronvolt (eV) is a unit of energy, but because of the mass–energy equivalence it can easily be converted to a unit of mass and is often used like one. In this context, the mass has units of eV/c2 (where c is the speed of light). The electronvolt and its multiples, such as the MeV (megaelectronvolt), are commonly used in particle physics.
- The atomic mass unit (u) is 1/12 of the mass of a carbon-12 atom, approximately 1.66×10−27 kg. The atomic mass unit is convenient for expressing the masses of atoms and molecules.
Pressure Conversion
Equals
Important Notes
- Various units are used to express pressure. The SI unit of pressure is the pascal (Pa), equal to one newton per square meter (N/m2 or kg·m−1·s−2). Similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and US customary systems. Other units of pressure such as bar, are also in common use.
- Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure and the torr is defined as 1⁄760 of this. Also, the technical atmosphere is 1 kgf/cm2 (98.0665 kPa, or 14.223 psi).
- The CGS unit of pressure is the barye (Ba), equal to 1 dyn·cm−2 or 0.1 Pa.
- Mathematically : Pressure p=F/A , where F is the magnitude of the normal force and A is the area of the surface on contact. Pressure is a scalar quantity. It relates the vector area element (a vector normal to the surface) with the normal force acting on it.
- Manometric units such as the centimeter of water, millimeter of mercury and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer.
Energy Conversion
Equals
Important Notes
- In the International System of Units (SI), the unit of energy is the joule. It is equal to the energy expended (or work done) in applying a force of one newton through a distance of one meter.
- Energy can also be expressed in many other units that are not part of the SI such as ergs, calories, British Thermal Units, kilowatt-hours and kilocalories, which require a conversion factor when expressed in SI units.
- The SI unit of energy rate (energy per unit time) is the watt, which is a joule per second. Thus, one joule is one watt-second and 3600 joules equal one watt-hour.
- The CGS energy unit is the erg and the imperial & US customary unit is the foot pound. Other energy units such as the electronvolt, food calorie or thermodynamic kcal (based on the temperature change of water in a heating process) and BTU are used in specific areas of science and commerce.
- Energy is essential to life and all living organisms. The sun, directly or indirectly, is the source of all the energy available on Earth.
Power Conversion
Equals
Important Notes
- In the International System of Units (SI), the unit of power is the watt (W) which is equal to one joule per second. The dimension of power is energy divided by time.
- Other common and traditional measures are horsepower (HP), comparing to the power of a horse; one mechanical horsepower equals about 745.7 watts.
- Some other units of power include ergs per second (erg/s), foot-pounds per minute, dBm, a logarithmic measure relative to a reference of 1 milliwatt, calories per hour, BTU per hour (BTU/h) and tons of refrigeration.
- The domestic electricity consumption is measured in terms of Kilowatt-hour (kWh). The kilowatt-hour is a composite unit of energy equal to one kilowatt (kW) of power sustained for one hour.
- All machines are typically described by a power rating. The power rating indicates the rate at which that machine can do work upon other objects. Thus, the power of a machine is the work/time ratio for that particular machine.
