In these interactions the energy and momentum of each particle may change, but the sum total of all the energy and the sum total of all the momentum remains constant with time: Now view the exchange f...In these interactions the energy and momentum of each particle may change, but the sum total of all the energy and the sum total of all the momentum remains constant with time: Now view the exchange from the reference frame in the right panel of Figure \PageIndex4:. A problem with four-momentum conservation exists in the region between the thin horizontal lines.
In Newtonian mechanics, position in space can be indicated with a three-dimensional vector. In Special Relativity, however, events are indicated using four coordinates: x=(t,x,y,z).
