单选题 Experienced baseball fielders can tell how far a ball is going to travel just by listening to the crack of the bat. If they didn't, they wouldn't stand a chance of catching it, claims a physicist in New York.
"When a baseball is hit straight at an outfielder, he cannot quickly judge the angle of the scent and the distance the ball will travel," says Robert Adair, a physicist at Yale University. If he relied purely upon visual information, the fielder would have to wait for about one-and-a-half seconds before he could tell accurately if the pitcher hit the ball long or short. By this time the ball may have travelled too far for him to reach it in time.
To stand a fighting chance of catching it, according to Adair, fielders must listen to the sound the ball hitting the bat to judge how far it will travel. There is anecdotal evidence to support this, he says. A former centre fielder told Adair: "If I heard a crack I ran out, if I heard a clunk, I ran in."
To test his hypothesis, Adair calculated how quickly a fielder could change direction if he had misjudged whether the ball was going long or short. The difference between the "crack" and "clunk” can he explained by how well the batter has hit the ball, and could mean a difference in running distance of as much as 30 metres, he told delegates at a meeting of the Acoustical Society of America in Chicago last week.
Scientists already knew that to hit a ball long the batter must strike it somewhere near the vibrational node of the bat, known as the sweet spot. Balls hit on the sweet spot generate fewer energy-sapping vibrations in the bat, allowing greater energy transfer to the ball. Conversely, mishit balls make the bat vibrate strongly and so do not travel as far.
Adair is quick to point out that this only applies to wooden bats, which are used in major league baseball. Aluminum bats, on the other hand, tend to produce a fairly uniform "ping” sound regardless of where you hit them.

单选题 According to Robert Adair, why can't an outfielder rely purely on visual information?

单选题 From paragraph 3 we can infer that a "crack" may mean ______.

单选题 If the bat vibrates very little, ______.

单选题 Adair points out that his theory can't be applied to aluminum bats because ______.

单选题 Which of the following statement is NOT TRUE according to the passage?

A、 If a baseball fielder cannot tell the distance a ball is going to travel by listening to the crack of the bat, they may lose the chance of catching it.
B、 If a fielder relies purely upon sound information, the ball may have traveled too far for him to reach it in time.
C、 The sound hit on the ball could mean a difference in running distance of as much as 30 meters.
D、 If the ball do not hit on the sweet spot, the ball cannot travel as far as possibl

【正确答案】 B

【答案解析】在第一段第一句就提到，“Experienced baseball fielders can tell how far a ball is going te travel just by listening to the crack of the bat．If they didn't，they wouldn't stand a chance of catching it”，有经验的棒球外野手可以通过倾听球拍的击打声来分辨球的运动距离，而无法做到这一点的话，则有可能把握不住接球的机会。所以A是正确的。在第二段提到，“If he relied purely upon visual information…the ball may have traveled too far for him to reach it in time．”所以B不正确，应该为visual而不是sound information。第三段中，“The difference between the crack and clunk…could mean a difference in running distance of as much as 30 meters”，所以C正确。第四段最后一句提到，“Conversely，mishit balls make the bat vibrate strongly and so do not travel as far．”相反地，如果没有击中sweet spot的话，会使拍子剧烈振动，从而无法击得远，所以D也正确。