The first pendulum clock, invented by Christiaan Huygens in 1656. Huygens (1658) Horologium, Opera Varia, Vol. 1 S. 1, Public Domain
DAY 1: Pendulums
From "beginning of chapter" to "...many other valuable uses."
DAY 2: Law of Uniform Acceleration I
From "[Now] [I]magine the following..." to "...weight of the object."
DAY 3: Law of Uniform Acceleration II
From "Just how fast do..." to "end of chapter."
There are great videos to go with this reading:
Apollo 15 Hammer-Feather Drop
Brian Cox visits world's biggest vacuum chamber
At the end of the video, Mr. Cox brings in Newton whom we don't encounter until next chapter. He also brings in some fun Einstein at the end. He also incorrectly refers to gravity as a force. It is better to say the force due to gravity.
CORRECTIONS (both editions)
If you have the original, one-volume edition, there is a potentially confusing typo in this chapter (it has been corrected in the newer edition). In several places the incorrect units are used for acceleration. However, in correcting it, a new error was introduced to the new edition.
speed or velocity = change in distance divided by time
acceleration = change in velocity divided by time
SU ch 4 (older, one volume)
pg. 28: They found that falling objects accelerate at 9.8 meters per second per second (32 feet per second per second). (a second "per second" should be added because it is an acceleration)
pg. 28: To make our calculations a little easier, let's round off the rate of acceleration from 9.8 meters per second per second to 10 meters per second per second. (a second "per second" should be added because it is an acceleration)
OM ch 2 (newer)
p. 25: That means that at the end of each second, an object is falling 9.8 meters per second faster than it did the second before. (the second "per second" should not be there because it is referring to a velocity)