Effective mass (solid-state physics) from both sides gives where is the th element of , is the th element of , and are the th and th elements of , respectively, and is the total energy of the particle according to the Planck–Einstein relation. The index is contracted by the use of Einstein notation (there is an implicit summation over ). Since Newton's second law uses the inertial mass (not the gravitational mass), we can identify the inverse of this mass in the equation above as the tensor This tensor expresses the change in group velocity due to a change in crystal momentum. Its
Detonation velocity detonation velocity of the explosive is calculated and is expressed in km/s. Detonation velocity Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. The data listed for a specific substance is usually a rough prediction based upon gas behavior theory (see Chapman-Jouguet condition), as in practice it is difficult to measure. Explosive velocities are always faster than the local speed of sound in the material. If the explosive is confined before detonation, such as in an artillery shell, the force produced is focused