A recreational motor boat on a lake is towing a 70-kg water skier. She holds on to a nylon tow rope of length 12 m with a cross sectional area of 2.0 10-5 m2. As the boat and she starts moving, she is subjected to a horizontal drag force of 125 N from the water. If she moves with an acceleration of 0.85 m/s2, by how much does the rope stretch? Young's modulus for nylon is 3.7 109 N/m2.

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 -