The car salesman tells you that the car can go from a stopped position to 60 miles per hour in 6 seconds. he is giving you the car's rate of

He tells you  (a speed) per (a time).  That's a rate of acceleration .

Let's find out what the acceleration is:

             (60 mile/hour) / (6 seconds)

         =    10  miles/hour-second

Weird units.  Let's convert to something easier.

           (10  mi/hr-sec) x (5280 ft/mi) x (1 hr / 3600 sec)

         =    14-2/3  ft/sec²  =  about 0.46 'G'

          about 4.47 meter/s²

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 -