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# science in three

Prefix: K, Kilo- = 1000 = 103.

Three laws of motion by Sir Isaac Newton (1687). The 1st law: An object will remain at constant velocity unless a non-zero force acts upon it. The 2nd law: The force will accelerate an object in the direction of that force; the acceleration is proportional to the force and inversely proportional to the object’s mass. The 3rd law: For every force, there is an equal and opposite force.

Three thermodynamics laws. The 1st law: Energy cannot be created or destroyed, but only converted from one form to another. The 2nd law: Heat cannot of itself pass from a colder to a warmer body. The 3rd law: The entropy of ordered solids reaches zero at the absolute zero of temperature.

Three Kepler’s laws on planets’ orbital movement around the Sun. The 1st law: Each planet’s orbit is an ellipse with the Sun at one focus. The 2nd law: The rate of area that swept by a planet along its orbit is constant. The 3rd law: The ratio of the semi-major axis to the square of the period is constant for all the planets.

The well-known “three-body problem” in mathematical physics, studied by many mathematicians D’Alembert, Leonhard Euler, Joseph-Louis Lagrange, Jacobi and Laplace…

3-dimensional (3D or 3-D) figure has length, width and height/depth (or 3 coordinates).

The number of means of heat transfer: heat connection, heat conduction and heat convection.

The number of different classifications of rock: igneous, metamorphic (or pyroclastic) and sedimentary.

The triple point of water is the thermodynamic temperature at which water forms an interface of 3 phases: solid, liquid and vapor: 0.01 oC (Celsius or centigrade) = 273.16 K (Kelvin) = 32.018 oF (Fahrenheit).

Frequency Ranges

 Range Names Uses 3 Hz – 300 Hz Extremely Low Frequency (ELF) Telegraph 300 Hz – 3 KHz Voice Frequency (VF) Telephone Circuitry 3 KHz – 30 KHz Very Low Frequency (VLF) High Fidelity 30 KHz- 300 KHz Low Frequency (LF) Maritime Mobile 300 KHz – 3 MHz Medium Frequency (MF) Navigational Radio, Land-maritime Mobile 3 MHz – 30 MHz High Frequency (HF) Maritime, Aeronautical, Amateur Radio 30 MHz – 300 MHz Very High Frequency (VHF) Maritime, Meteorological Communication, Television 300MHz – 3 GHz Ultra High Frequency (UHF) Television, Military, Low Range Radar 3 GHz – 30 GHz Super High Frequency (SHF) Space, Satellite, Microwave 30 GHz – 300 GHz Extremely High Frequency (EHF) Radio Astronomy

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