Abullet of mass m = 40~\text{g}m=40 g, moving horizontally with speed vv, strikes a clay block of mass m = 1.53m=1.53 kg that is hanging on a light inextensible string of length l = 0.587l=0.587. the bullet becomes embedded in the block, which was originally at rest. what is the smallest value of vv which would cause the block-on-a-string to swing around and execute a complete vertical circle?

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 -