Rawly has a mass of 79.0 kg, and he is sledding down a hill that is 29.5 m tall. As he goes down the hill, his gravitational potential energy is converted into kinetic energy. When he has descended 21.0 m down the hill, how much kinetic energy and gravitational potential energy does he have? A. GPE=16,300 J; KE=6590 J.
B. GPE=6590 J; KE=16300 J.
C. GPE=22900 J; KE=6590 J.
D. GPE=0 J; KE= 22900 J

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 -