15. The period of the vertical oscillations of a mass hanging from a spring is known to be constant.
(a) A student times single oscillations with a stopwatch. In 10 separate measurements, the
stopwatch readings were:
1.8 s, 1.9 s, 1.7 s. 1.9 s, 1.8 s, 1.8 s, 1.9 s. 1.7 s, 1.8 s, 1.8 s.
What is the best value obtainable from these readings for the time of one oscillation?
Explain how you arrive at your answer.
best value =
explanation
(b) Describe how, using the same stopwatch, the student can find the period of oscillation
more accurately

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 -