Assertion: photon's momentum | /r/HasProperty | conserved
Facets:
Source sentences:
text: Notice that energy is conserved, momentum is conserved, but mass is not: the final mass is zero, even though the initial mass is 2 times M.
text: Again, energy is conserved, momentum is conserved, charge is conserved, but mass is not; the initial mass was 2M, the final mass is 2m.