metric_units.txt   MKS metric units are:
Meter for Length   L
Kilogram for Mass  M
Second for Time    T

                                  dimensionality     units
distance in meter                            L       meter
time in second                               T       second
mass in kilogram                             M       kilogram
velocity in meter/second                     L/T     meter per second
acceleration in meter/second^2               L/TT    meter per second^2
area in meter^2                              LL      square meter
volume in meter^3                            LLL     cubic meter
force in newton=kilogram*meter/second^2      ML/TT   newton
              F=ma 
pressure in pascal=kilogram/(meter*second^2) M/LTT   newton per meter^2
                  =newton/meter^2
density in kilogram/meter^3                  M/LLL   kilogram per meter^3
energy in newton*meter=pressure*volume       MLL/TT  joule  
dynamic viscosity in kilogram/(meter*second) M/LT    kilogram per meter second
kinematic viscosity in meter^2/second        LL/T    meter^2 per second
momentum in kilogram*meter/second            M/LT    kilogram meter second
moment of inertia in kilogram*meter^2        MLL     kilogram meter^2
stress (pressure) in newton/meter^2          ML/TT   newton per meter^2
strain (deformation) in length meter         L       meter
angle in radians  2 Pi = 360 degrees         phi     radians

temperature may be in degrees fahrenheit, degrees celsius or degrees kelvin

Planet Earth
mass          5.97 10^24   kilogram
radius        6,378        kilometer
              6.378 10^6   meter
diameter      12,756       kilometer
              12.756 10^6  meter
circumference  40.074 10^6  meter  at equator
volume        1.083 10^24  cubic meter
              108.3 10^10  cubic kilometer
area          128.1 10^12  square meter
              196.9 10^6   square miles
gravity       9.8          meters per sec^2
rotation      24           hours
              1440         minute
	      86,400       second
speed equator 463.9 10^3   meter per second
              0.4639       kilometer per second
population    7.9 billion  at 2021

universal gravitational constant G = 6.674 10^-11
Force = G mass1 mass2 / distance^2  distance center of mass1 to center of mass2
Centripetal force = mass velocity^2 / radius


Temperature conversion:
// temperature   fahrenheit  celsius   kelvin  degrees
//               -459.67     -273.15     0.0     absolute zero
//                 32           0      273.15    water H2O freeze
//                212         100      373.15    water H2O boils
//               2750        1510     1783.15    some steel melts
// a water molecule having two hydrogen atoms and one oxygen atom
// for water at pressure 1 atmosphere
// a copper wire at absolute zero has zero resistance, super conducting

celsius = (fahrenheit-32.0)*100/(212-32)

kelvin = (fahrenheit-32.0)*100/(212-32) + 273.15;

fahrenheit = celsius*(212-32)/100 + 32.0

kelvin = celsius + 273.15

fahrenheit = (kelvin-273.15)*(212-32)/100 + 32.0

celsius = kelvin-273.15;