To the nearest second, how many seconds elapse between when a flash of lightning is seen and when the clap of thunder is heard if the lightning
a. a kilometer away?
b. 1 mile away (1.6 km away)?

a. 2.9 s

First of all, we can assume that the light of the lightning reaches us instantaneously, since the speed of light is very large and so light takes a negligible time to reach us.

Secondly, the speed of sound in air is

So, the difference in time between the moment we see the flash of the lightning and the moment we hear the thunder is simply given by the time it takes for the sound wave to cover the distance of  d = 1 km = 1000 m, so:

b. 4.7 s

This part of the exercise is exactly identical to the previous one, except for the fact that this time the distance that the sound should cover is

d = 1.6 km = 1600 m

Therefore, the time difference is

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;

this is an example of "committed" time.

committed time, as contracted time, takes need over essential and available time since it is seen as profitable work. it alludes to the time allotted to keep up a home and family. at the point when a man is commuting using committed time this individual may feel that the drive is an obligation to family, for example, strolling youngsters to class or driving a mate to work. contracted and committed time clients may feel that their commute could really compare to the commute of important or leisure time clients on the grounds that their commute is profitable work. in this manner, they might be more disposed to pick a mechanized method of movement.