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TOEFL Reading Gratis 4

Question 31-38

   The ability of falling cats 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. If a cat has body cannot change unless an external torque speeds it up or slows it down. If a cat has spin when it is released and experiences no external torque, it ought not to be able twist around as it falls.
   In the speed of its execution, the righting of a tumbling cat resembles a magicians trick. The gyrations of the in midair are too fast for human eye to follow, so the process is 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.
   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 the front 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 and 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 could not be sure how it happened until they increased the speed of their perceptions a thousand fold.

(QUESTION) What does the passage mainly discuss?
The word ‘process’ in line 7 refers to
Why are the photographs mentioned in line 16 referred to as an ‘experiment’?
Which of the following can be inferred about high-speed photography in the late 1800’s?
The word ‘rotates’ in line 15 is closest in meaning to
According to the passage, a cat is able to right itself in midair because it is
The word ‘readily’ in line 18 is closest in meaning to
How did scientists increase ‘the speed of their perceptions a thousand fold’ (line 19-20)?
According to the passage, the population of the United States was firs classified as rural or urban in

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