首页
登录
职称英语
A pilot cannot fly a plane by sight alone. In many conditions, such as flyin
A pilot cannot fly a plane by sight alone. In many conditions, such as flyin
游客
2025-02-02
15
管理
问题
A pilot cannot fly a plane by sight alone. In many conditions, such as flying at night and landing in dense fog, a pilot must use radar, an alternative way of navigating. Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. The basic principle of radar is exemplified by what happens when one shouts in a cave. The echo of the sounds against the walls helps a person determine the size of the cave. With radar, however, the waves are radio waves instead of sound waves. Radio waves travel at the speed of light, about 300, 000 kilometers in one second. A radar set sends out a short burst of radio waves: Then it receives the echoes produced when the waves bounce off objects. By determining the time it takes for the echoes to return to the radar set, a trained technician can determine the distance between the radar set and other objects. The word "radar," in fact, gets its name from the term "radio detection and ranging." "Ranging" is the term for detection of the distance between an object and the radar set. Besides being of critical importance to pilots, radar is essential for air traffic control, tracking ships at sea, and for tracking weather systems and storms. [br] According to the passage, what can a radar detect besides location of objects?
选项
A、Size.
B、Weight.
C、Speed.
D、Shape
答案
C
解析
细节题型见本文第三行:Since human eyes are not very good at determining speeds of approaching objects, radar can show a pilot how fast nearby planes are moving. (由于人眼并不擅长判定物体接近的速度,雷达就被用来给飞行员显示附近的飞机速度有多快);因此可知雷达除了可探测物体的方位,还能探测物体的速度,选项C为答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3939643.html
相关试题推荐
Apilotcannotflyaplanebysightalone.Inmanyconditions,suchasflyin
Apilotcannotflyaplanebysightalone.Inmanyconditions,suchasflyin
Apilotcannotflyaplanebysightalone.Inmanyconditions,suchasflyin
Apilotcannotflyaplanebysightalone.Inmanyconditions,suchasflyin
Apilotcannotflyaplanebysightalone.Inmanyconditions,suchasflyin
Apilotcannotflyaplanebysightalone.Inmanyconditions,suchasflyin
Youcannotsaythatthedesireformaterialadvantageisthebasicmotiveinhum
Thoughtheimitationjewelrycanfoolmanypeople,theycannot______uptoanexp
Hecannotseeanythingwithouthisglasses,sohemadea______ofrememberingto
Somemedicalconditionscanoftencurethemselves______,withoutmedicalinterve
随机试题
Inhernovelof"Reunion,AmericanStyle",RonaJaffesuggeststhataclass
Advertisementcanbethoughtofas"themeansofmakingknowninordertobu
根据《中华人民共和国标准化法》、关于标准的正确说法是()。A.国家标准分为
所示空间桁架,杆cd轴力为( )kN。 A.2 B.4 C. D.
HSKandCETare_____.A.Criterion-related
Thechangeinthatvillagewasmiraculou
一次多量空气进入静脉可引起猝死,最低进入空气量约为( )。A.5mL B.1
关于建设项目安全评价的说法,正确的有( )。A.安全评价的原理包括类推原理 B
安全防范系统的线缆敷设,下列哪项符合规范的要求?()A.明敷设的信号线路与具有
关于施工中产生的固体废物污染环境防治的说法,正确的是( )。A.施工现场的生活
最新回复
(
0
)