Question

[Lê Quỳnh Anh]

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

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 unless an external torque speeds it up or slows it down. If a cat has no spin when it isreleased 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 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.

          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 end result. The explanation was that while nobody 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 thousandfold.

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

A. The photographs were not very clear

B. The purpose of the photographs was to explain the process

C. The photographer used inferior equipment

D. The photographer thought the cat might be injured

Answer 1

[Dương Hoàn Anh]

Đáp án B

Thông tin: 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.

Dịch nghĩa: Hoặc là con mắt được đẩy nhanh tốc độ, hoặc là sự rơi của con mèo chậm lại để hiện tượng này được quan sát. Một thế kỷ trước, điều thứ nhất đã được thực hiện bằng phương tiện của nhiếp ảnh tốc độ cao sử dụng các thiết bị sẵn có ngày nay ở bất kỳ hiệu thuốc nào. Nhưng trong thế kỷ mười chín, sự chụp phim của một con mèo rơi xuống tạo thành một thí nghiệm khoa học.

Như vậy những bức ảnh được gọi là thí nghiệm bởi vì mục đích của nó là ghi lại hình ảnh và giải thích hiện tượng về con mèo.

          A. The photographs were not very clear = Các hình ảnh không phải là rất rõ ràng.

Không có thông tin như vậy trong bài.

          C. The photographer used inferior equipment = Các nhiếp ảnh gia sử dụng thiết bị kém.

Không có thông tin như vậy trong bài.                   

          D. The photographer thought the cat might be injured = Các nhiếp ảnh gia cho rằng con mèo có thể bị thương.

Không có thông tin như vậy trong bài.