a race car is travelling at +76m/s when it slows down at -9m/s2 for 4 seconds. whats his new velocity?

A :-) for this question we should apply
v = u + at
Given - u = 76 m/s
v = ?
a = - 9 m/s^2
t = 4 sec
Solution -
v = u + at
v = 76 + ( -9 ) x 4
v = 76 - 9 x 4
v = 76 - 36
v = 40 m/s

.:. The new velocity is 40 m/s

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 -