Arailroad freight car with mass 30,000 kg collides is moving in the +x direction at 2.00 m/s when it collides with a stationary caboose car. the two cars couple together, and move down the track at vf. during the collision, 50.0% of the original kinetic energy is lost to thermal energy, sound, vibrations, and so on. find the mass of the caboose in kg.

Because shotguns bullets ricochet

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -