NGeSHOT (posi+ive blog): READING COMPREHENSION

The ability of falling cats to right themselves in midair and land on their feet has

been a source of wonder for ages. Biologists long regarded it as an example of

adaptation by natural selection, but for physicists it bordered on the miraculous

Newton’s laws of motion assume that the total amount of spin of a body cannot change

(5) unless an external torque speeds it up or slows it down. If a cat has no spin when it is

released and experiences no external torque, it ought not to be able to twist around as it

falls.

In the speed of its execution, the righting of a tumbling cat resembles a magician’s

trick. The gyrations of the cat in midair are too fast for the human eye to follow, so the

(10) process is obscured. Either the eye must be speeded up, or the cat’s fall slowed down

for the phenomenon to be observed. A century ago the former was accomplished by

means of high-speed photography using equipment now available in any pharmacy.

But in the nineteenth century the capture on film of a falling cat constituted a scientific

experiment.

(15) The experiment was described in a paper presented to the Paris Academy in 1894.

Two sequences of twenty photographs each, one from the side and one from behind,

show a white cat in the act of righting itself. Grainy and quaint though they are, the

photos show that the cat was dropped upside down, with no initial spin, and still landed

on its feet. Careful analysis of the photos reveals the secret: As the cat rotates as the front

(20) of its body clockwise, the rear and tail twist counterclockwise, so that the total spin

remains zero, in perfect accord with Newton’s laws. Halfway down, the cat pulls in its

legs before reversing its twist and then extends them again, with the desired end result.

The explanation was that while no body can acquire spin without torque, a flexible one

can readily change its orientation, or phase. Cats know this instinctively, but scientists

(25) could not be sure how it happened until they increased the speed of their perceptions a

thousandfold.

Reading Comprehension 85

Question 1

What does the passage mainly discuss?

	A. The explanation of an interesting phenomenon
	B. The differences between biology and physics.
	C. Miracles in modern science
	D. Procedures in scientific investigation

Question 2

The word "process" in line 10 refers to

	A. a scientific experiment
	B. high-speed photography
	C. the righting of a tumbling cat
	D. the cat's fall slowed down

Question 3

Why are the photographs mentioned in line 16 referred to as an "experiment"?

	A. The purpose of the photographs was to explain the process.
	B. The photographer thought the cat might be injured.
	C. The photographer used inferior equipment
	D. The photographs were not very clear.

Question 4

Which of the following can be inferred about high-speed photography in the late 1800's?

	A. The resulting photographs are difficult to interpret.
	B. The necessary equipment was easy to obtain.
	C. It was a relatively new technology.
	D. It was not fast enough to provide new information.

Question 5

The word "rotates" in line 19 is closest in meaning to

	A. controls
	B. turns
	C. touches
	D. drops

Question 6

According to the passage, a cat is able to right itself in midair because it is

	A. intelligent
	B. frightened
	C. flexible
	D. small

Question 7

The word "readily" in line 24 is closest in meaning to

	A. easily
	B. slowly
	C. certainly
	D. only

Question 8

How did scientists increase "the speed of their perceptions a thousandfold" (lines 25-26)?

	A. By observing a white cat in a dark room
	B. By dropping a cat from a greater height.
	C. By studying Newton's laws of motion.
	D. By analyzing photographs