tnt is an example of a high explosive
The velocity with which the reaction process propagates in the mass of the explosive. Most commercial mining explosives have detonation velocities ranging from 1800 m/s to 8000 m/s. Today, velocity of detonation can be measured with accuracy. Together with density it is an important element influencing the yield of the energy transmitted for both atmospheric over-pressure and ground acceleration. By definition, a ``low explosive,'' such as black powder, or smokeless gunpowder has a burn rate of 171--631 m/s. In contrast, a ``high explosive,'' whether a primary, such as detonating cord, or a secondary, such as TNT or C-4 has a significantly higher burn rate.
Explosive material