The fundamental constant of physics, the Boltzmann constant, is one of the seven “defining constants” that have been given exact definitions. It is defined to be exactly 1.380649×10−23 J⋅K−1. This constant is related to the average relative kinetic energy of particles in a gas with the thermodynamic temperature of the gas.

Gravitational Constant (G)
The gravitational constant, G, is utterly important for any engineer. It helps determine the force between two masses.