An astronaut is being tested in a centrifuge. the centrifuge has a radius of 12.0 m and, in starting, rotates according to θ = 0.370t2, where t is in seconds and θ is in radians. when t = 5.00 s, what are the magnitudes of the astronaut's
(a) angular velocity,
(b) linear velocity,
(c) tangential acceleration, and
(d) radial acceleration?

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 -

The answer is d) by requesting advice on science internet sites