Consider a ball thrown at an angle of 200 above the horizontal and another ball thrown at 200 below the horizontal. Both balls thrown with the same initial speed of 20 m/s from the top of the Science Center. Draw the motion diagram for both cases indicating the velocity and acceleration vectors. Explain the physics of these two situations and calculate the time taken for the balls to reach the ground.

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 -