Units Of Measurements

• Metric system uses the units of kilogram, meter, and second for measuring distance, mass, and time respectively.
• English system uses foot, pound, and second for measuring distance, weight, and time respectively.
• International System of Units or SI was published as a result of an international agreement in 1960.
• Si converts fundamental units in a more convenient way using prefixes such as kilo, mega, giga, deci, centi, milli, and micro.
• A mole is defined as the number of atoms equal to Avogadro's constant, approximately 6.02 x 10^23.
• The International System of Units is based on seven base units which are length (meter), mass (kilogram), time (second), electric current (ampere), thermodynamic temperature (kelvin), amount of substance (mole) and luminous intensity (candela).
• Physical Quantities includes Mass, Weight, Length, Time, Volume, Temperature, Pressure, Density, and Specific gravity.
• Mass refers to the quantity of matter contained within an object.
• Length refers to the measurement of how far apart two points are from one another.
• Time refers to the duration of an event.
• Temperature refers to the degree of hotness or coldness of an object.
• Pressure refers to the force exerted per unit area.
• Specific Gravity is the ratio of density of substance to that of water at standard temperature and pressure (STP).
• Volume is the amount of space occupied by a substance or object. It is measured in cubic meters or liters. It is derived from length.
• Weight is the force of gravity acting on an object, measured in newtons (N).
• Density is the mass of a substance per unit volume.
• Derived Quantities are the quantities that are derived from the original quantity. It includes units like Velocity, Speed, Area, Momentum and Acceleration.