:force = mass x acceleration : a planet moves faster in the part of its orbit nearer the sun and slower when farther from the sun, sweeping out equal areas in equal times. : the orbit of each planet about the sun is an ellipse with the sun at one focus. : for any force, there is an equal and opposite reaction force. : an object moves at constant velocity if there is no net force acting upon it. : more distant planets orbit the sun at slower average speeds, obeying the precise mathematical relationship p2 =a3.

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 -

A. they hold atoms  together with a molecule.its a force that exist between molecules. hope this .

It's because 3 if it was 10 it wouldn't look right do it goes up to 4d