题干

酒后驾驶会导致许多安全隐患,是因为驾驶员的反应时间变长,反应时间是指驾驶员从发现情况到采取制动的时间.下表中“思考距离”是指驾驶员从发现情况到采取制动的时间内汽车行驶的距离,“制动距离”是指驾驶员从发现情况到汽车停止行驶的距离(假设汽车制动时的加速度大小都相同).

速度/(m•s1

思考距离/m

制动距离/m

正常

酒后

正常

酒后

15

7.5

15.0

22.5

30.0

20

10.0

20.0

36.7

46.7

25

12.5

25.0

54.2

66.7

分析上表可知,下列说法正确的是(  )

A:驾驶员正常情况下反应时间为0.5 s

B:驾驶员酒后反应时间比正常情况下多0.5 s

C:驾驶员采取制动措施后汽车的加速度大小为3.75 m/s2

D:若汽车以25 m/s的速度行驶时,发现前方60 m处有险情,酒后驾驶不能安全停车

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答案(点此获取答案解析)

A,B,D

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    On 20th July 1969, millions of people saw Neil Armstrong take his first steps in space on television. Armstrong got out of the spacecraft Apollo 11, touched the ground of the moon and said, “That's one small step for man, one giant leap for mankind.”

    A conspiracy(阴谋)theory has existed since the night of his lunar handing. Armstrong's achievements were considered amazing, but people wondered if it really happened. Many people believe that the scene on the moon wasn't real. Rumours spread throughout coffee shops, street comers, and newspapers, but it soon died down.

    But theories resurfaced in 2001 Suspicion began when an American television network aired a program called Conspiracy Theory: Did We Land on the Moon? The show argued that NASA did not have the money for such a voyage, and that the whole scene was probably filmed in a movie studio. Many critics say that there were no stars in the background during the lunar landing, so it must have been a fake. They also point out that the American flag that was posted was waving. How could that be if there is no wind on the moon?

    NASA(National Aeronautics and Space Administration)has denied these rumours many times. They explained that now photographers can capture the brightness of the astronauts with the dimness of the stars behind them. Also, they said that the flag was waving because the astronauts were pulling it back and forth trying to get it deeper into the rock. NASA also points out that the television program fails to mention that Armstrong and his team brought back 800 pounds of rock from the moon.

    Nell Armstrong is seen as a national icon in the US and his lunar landing is one of the most historic events in the country's history. But either way, this conspiracy theory still exists today.