> The amount of principal and derivative By: Taufiqullah Neutron (Masteropik) The amount of principal The amount of principal is the amount that the unit has been defined prior first. Seven basic quantities in the SI unit system are: Length (meters) Mass (kg) Time (second) Strong electric current (ampere) Temperature (kelvin) Light intensity (candela) Amount of substance (mole) Units such as meters, kilograms, and the second is already defined first. What is the definition of units of principal amount of these? In the following explanation will be presented definitions of three basic quantities of length, mass, and time, while unit Other quantities will be discussed when we discuss the subject concerned with the amount of vine. Long The standard unit for length is the meter in the SI. System of units based on the meter as a standard measurement system called metric. At first, the meter is defined as one ten-millionth the distance between equator and north pole of the earth is measured through the meridian through the city of Paris. As a standard meter, was made a metal rod platinum-iridium, which contained both ends of each stroke, where the distance between two scratches are equal to 1 meter. In 1960, a standard meter redefined as 1,650,763.73 times the wavelength in vacuum of the color spectrum orange-red krypton-86 atoms. This is done to re-defining increase the ease of a standard meter to be made replica, in addition to to increase accuracy. However, even this definition does not re- last long, only about 23 years. In 1983, one meter defined as the distance traveled by light in vacuum during 1/299.792.458 second. With this last definition, complete meters as standard units meet the requirements specified standard units in front. Mass The mass of an object is a number of substances contained in an object. Mass units in the SI unit system is kilogram. As a standard for the kilogram, the kilogram standard was made, which is a metal cylinder made of platinum-iridium, which is now This is stored in Sevres, near Paris. Initially one kilogram same with a mass of 1000 cm ³ of pure water at a temperature where the density maximum, which is 4 º C. But mistakes happen, because it turns out one kilogram exactly is 1000.028 cm ³ of water. In everyday conversation, we often confuse the sense mix mass with weight, but they are different. Weight is the amount of force experienced by objects due to gravity on the object. For daily use, is not a confusion of terms problem, but in physics or an exact science, the definition of mass and weight should really be distinguished. Has units of mass and weight different, mass has units of kilograms, while the weight has Newton unit. The main difference between mass and weight is that the masses do not depend on the place where the object is located, while the weight depending on where the object is located. So the weight change according to the place. Left Standard units for time are seconds, which was originally defined 1/86.400 day as the sun. But when scientists found that solar day is reduced about 0.001 seconds every century, then the second 1/86.400 redefined as solar day in 1900. In 1967, the second was redefined as the time interval from 9192631770 oscillation of the radiation generated by transitions in cesium-133 atom. Tool measuring time using a cesium atom is cesium atomic clock, which have a very high accuracy, ie during the 3000 year only have a second mistake. The amount of derivatives. Most of the values which we use in physics and sciences terapannya (including fluid mechanics and hydraulics, and heavy equipment) units have a combination of units principal amount. Such quantities, which determined its unit based on the principal amount of units, called the scale derivative. Examples of the magnitude of this derivative is the area of a square area. Same broad length times width, where length and width are both unit length. So vast is the quantity derived from length scale multiplication with a scale length. Example: Other: speed (distance divided by time), pressure (force divided by area), the volume of beam (Length x width x height), discharge (volume divided by time). We know that speed is the distance (scale length) divided by time. So speed is a derivative quantity obtained by dividing the amount of long with the amount of time. How unit quantities derived from them? It is clear that the units for the amount of derivatives in accordance with how the derived quantities were obtained from a combination of basic quantities. Because the same large scale multiplication of two long, then the unit area together with the multiplication of two units of length, namely meter x meter = meter square = m². The unit for speed is the unit of length divided by unit time, ie meters per second = m / s. It is clear here that that the units derivative quantities that follow describe the scale derivative. Unit speed is m / s, mean speed equal to the length (distance) divided time. The unit for volume is m beam, means the volume is the length times the length times the length. Density has the units kg / m³, mean mass type is the mass divided by volume.