A pickup truck is moving at 25 m/s with a toolbox of mass m resting on the bed of the truck 2.5 m behind the cab. Suddenly the brakes are applied, causing the toolbox to slide, and the truck comes to a stop in 4.7 s. The coefficient of kinetic friction between the toolbox and the bed of the truck is 0.28. After the brakes are applied, how much time elapses before the toolbox strikes the cab?

Ido not know at all

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 -