首页
登录
职称英语
An airplane flies because its wings push down on the air flowing past them, a
An airplane flies because its wings push down on the air flowing past them, a
游客
2023-09-26
50
管理
问题
An airplane flies because its wings push down on the air flowing past them, and in reaction, the air pushes up on the wings. When an airplane is level or rising, the front edges of its wings ride higher than the rear edges. The angle the wings make with the horizontal is called the angle of attack. As the wings move through the air, this angle causes them to push air flowing under them downward. A sleeper angle of attack will cause the wings to push more air downward. The third law of motion voiced by English physicist Isaac Newton states that every action produces an equal and opposite reaction. In this case, the wings pushing air downward is the action, and the air pushing the wings upward is the reaction. This causes lift, the upward force on the plane, Lift is often explained using Bernoulli’s principle, which states that, in some circumstances, a faster moving fluid(流体) (such as air)will have a lower pressure than a slower moving fluid. The air on the top of an airplane wing is at a lower pressure than the air underneath the wing, but this is an effect of lift, not its cause.
Lift is one of the four primary forces acting upon an airplane. The others are weight, thrust, and drag. Weight is the force that offsets lilt. because it acts in the opposite direction. The weight of the airplane must be overcome by the lift produced by the wings, if an airplane weighs 4.5 metric tons, then the lift produced by its wings must be greater than 4.5 metric tons in order for the airplane to leave the ground. Designing a wing that is powerful enough to lift an airplane off the ground, and yet efficient enough to fly at high speeds over extremely long distances, is one of the marvels of aircraft technology.
选项
答案
Why does an airplane fly?
解析
根据第一句话“An airplane flies because its wings push down on the air flowing past them,and in reaction,the air pushes up on the wings.”和全篇文章的意思得出。
转载请注明原文地址:https://tihaiku.com/zcyy/3046996.html
相关试题推荐
Thisarticleiswellwrittenbecausespecialattention________tothechoiceofw
Youhavetoraisethequalityofyourproductsbecausebuyersinthosecountries
ZhangGuimeihasearnedtherespectofpeoplebecauseshe________herselffull-t
Jameisunhappybecauseeveryonewenttothedance______her.A、against.B、forC
TomtooknonoticeofwhatIwassayingbecausehethoughtI(cheat)______him.
Shegaveupherjobasanursebecauseshefoundthechildrentoodifficult____
[audioFiles]audio_ehaz20046_001(20046)[/audioFiles]A、Becauseshelikestolive
[audioFiles]audio_ehaz20046_001(20046)[/audioFiles]A、Becausehe’llwritearepo
WhydoestheGmailTeamwritetotheGmailusers?Becausetheuserhasn’tusedh
WhydoestheGmailTeamwritetotheGmailusers?Becausetheuserhasn’tusedh
随机试题
Whatisthediscussionmainlyabout?[br]Accordingtotheprofessor,whathasm
[originaltext]Architectureistobuildingasliteratureistotheprinted
高渗性脱水补液应选择A、等张含钠溶液 B、5%葡萄糖 C、1/2张含钠液
下述致肺部感染的厌氧菌中,哪种对青霉素不敏感A.消化球菌属 B.核粒梭形杆菌
某患者夜间突发急腹症被送到某医院看急诊,初诊为急性胆囊炎。负责医生因自己年轻,怕
共用题干 林先生2014年因病去世,家中有房屋两套,市价约值人民币200万元,
共用题干 TrafficJams一NoEndinSight1Traf
学生主体性的形成,既是教育的目的,也是教育成功的()A.条件 B.任务 C
流动性风险的内部因素包括()。A.表外业务如贷款承诺、期权、信贷衍生工具及其他
企业库存量过小,可能产生的问题是()。A.造成产品和原材料的有形损耗和无
最新回复
(
0
)