Aprofessional diver steps off of a cliff that is 18 m high. draw a sketch of the cliff, defining your origin and final position. (careful with negative and positive signs.) unlike the wb assignment, assume the diver jumps up first and has an initial vertical velocity is 4 m/s. (ignore air resistance.) (a) how long does it take the diver to hit the water? (b) what's the diver's velocity on impact with the water? (careful with negative and positive signs.)

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 -