首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
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
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
admin
2010-01-13
122
问题
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.
Adair points out that his theory can’t be applied to aluminum bats because ______.
选项
A、the "ping” sound is too vague for a fielder to catch
B、with the aluminum bats the batter always hits the ball stronger
C、they don’ t produce different sounds of "crack" and "clunk"
D、the sounds they produce may interfere with the fielder’s judgment
答案
C
解析
Adair在最后一段指出,铅质球棒无论球击在何处发出的都是同样的一声“呼”。
转载请注明原文地址:https://kaotiyun.com/show/djmi777K
0
在职申硕(同等学力)英语
相关试题推荐
Courageouspeoplethinkquicklyandactwithouthesitation.
Duringalltheseyearsofabsence,hehad______atenderfeelingforhismotherandthefamily.
Hiseffortofdecadesbeganto______Hecametobewell-knownforhisfindings.
Chinesefarmersaremostlylivingasimpleandthriftylifeasitistoday.
Mysurpriseoverthepastfewwintershasbeenthepersonalitytransformationmyparentsgothrougharoundmid-Decemberasthey
Whatisimpliedby"theyoungeronesaresurroundedbymorechildren’slanguageonaveragethantheolderkids"(Para.3)?What
Somemedicalconditionscanoftencurethemselves______,withoutmedicalintervention.
Experiencedbaseballfielderscantellhowfaraballisgoingtotraveljustbylisteningtothecrackofthebat.Iftheydidn
Ihaveaninfatuation(迷恋)withautumn.Thecolorsoftheseason,andthesmells,havealwaysthrilledme.Ihavealwaysfoundjoy
Woman:WhatdoyouthinkofDr.White’schemistryclass?Man:Nowthere’sateacherwhoknowshersubject!Question:Whatdoesthe
随机试题
症见腹痛肠鸣,泻下粪便臭如败卵,泻后痛减,脘腹胀满,嗳腐酸臭,不思饮食,舌苔垢浊,脉滑,宜选用
流行病学实验研究的人群来自
Ts细胞的调节作用主要是通过
以下所列药物中,治疗手足浅表性真菌感染的处方药是
报表系统的主要功能是()。
对于A、B、C类不同的库存,盘点的周期也是不同的,下列对盘点周期描述正确的是()。
鸟类站在高压电线上不会触电致死是由于( )。
A、枯燥的生活已经远去,代之而来的是五光十色的现代生活。B、该协议书包括了工体大屏幕下通栏广告在内的5块广告牌,1项运动员号码广告等共7项广告。C、如果不加以控制人口,就会严重影响社会经济的顺利发展。D、有关人士希望把世界遗产教育纳入中学教学课程之中
Historian:IntheDrindianEmpire,censuseswereconductedannuallytodeterminethepopulationofeachvillage.Villagecensus
Animalsperformmanyusefulandentertainingjobs.Dogsareparticularlyvaluableguidingtheblind,protectingproperty,
最新回复
(
0
)