Day4 -5-6 SPACE AND TIME
NEW WORDS
1. (For example, the acceleration is twice as great if the force is
twice as great.) The acceleration is also smaller the greater the mass (or quantity of matter) of the body.
acceleration??
D: 1.the act of accelerating; increase of speed or velocity.
? ? ?2.a change in velocity.?
e,g,This leaves room for someaccelerationof the pace of withdrawals, an option the White House is reported to be considering.
velocity ?/v??l?s?ti/
?D: 1. rapidity of motion or operation; swiftness; speed:
eg.a high wind velocity.
2.Mechanics.the time rate of change of position of a body in a specified direction.
3.?the rate of speed with which something happens; rapidity of action or reaction.
eg.But Galston says what made the difference for Reagan was also the?velocity?of the change.
If the law?were that the gravitational attraction of a star went down faster or increased more rapidly with distance, the?orbits of the planets would not be elliptical, they would either spiral in to the sun or escape from the sun.
elliptical?
D: pertaining to or having the form of an?ellipse.
eg. The same goes for theellipticalmachine hunger strike, which also comes off as tonally deficient, to say the least.
Nevertheless,?Roemer’s achievement, in not only proving that light travels at a finite speed, but also in measuring that speed,?was remarkable – coming as it did eleven years before Newton’s publication ofPrincipia Mathematica.A proper?theory of the propagation of light didn’t come until 1865, when the British physicist James Clerk Maxwell?succeeded in unifying the partial theories that up to then had been used to describe the forces of electricity and?magnetism. Maxwell’s equations predicted that there could be wavelike disturbances in the combined?electromagnetic field, and that these would travel at a fixed speed, like ripples on a pond.
equation
D: 1.the act ofequatingor making equal; equalization:
the symbolic equation of darkness with death.
2.?equally balanced state; equilibrium.
3.?Mathematics.an expression or a proposition, often algebraic, asserting the equality of two quantities.
4.?Also calledchemical equation.Chemistry.a symbolic representation showing the kind and amount of the starting materials and products of a reaction.
eg. They provide the one real opportunity during a campaign for candidates to signficantly change theequationand move the numbers
electromagnetic
D. of or relating to?electromagnetism?or electromagnetic fields
Contemporary Examples
Theelectromagneticforce between the electrons lets you pick up the cup, counteracting gravity in the process.
實在不行了今天，未完待續(xù)
A proper?theory of the propagation of light didn’t come until 1865, when the British physicist James Clerk Maxwell?succeeded in unifying the partial theories that up to then had been used to describe the forces of electricity and?magnetism.
propagation ?noun
1.the act of?propagating.
2.the fact of beingpropagated.
3.multiplication by natural reproduction.
4.transmission or dissemination.
propagate?
D: to spread (a report, doctrine, practice, etc.) from person to person; disseminate.?
EG. Anti-abortion organizations tend to tend to?propagatethe idea that the procedure is dangerous and unproven.
He was stern but never oppressive – we knew abuse of power and would notpropagateit in our personal lives.
stern
adjective,sterner,sternest.
1.firm, strict, or uncompromising:
stern discipline.
2.hard, harsh, or severe:
a stern reprimand.
3.rigorous or austere; of an unpleasantly serious character:
stern times.
4.grim or forbidding in aspect:
a stern face.
Maxwell’s equations predicted that there could be wavelike disturbances in the combined?electromagnetic field, and that these would travel at a fixed speed, like ripples on a pond. If the wavelength of?these waves (the distance between one wave crest and the next) is a meter or more, they are what we now call?radio waves. Shorter wavelengths are known as microwaves (a few centimeters) or infrared (more than a?ten-thousandth of a centimeter). Visible light has a wavelength of between only forty and eighty millionths of a?centimeter. Even shorter wavelengths are known as ultraviolet, X rays, and gamma rays.
disturbance ?noun
Synonyms? perturbation, confusion. See?agitation.5.confusion, tumult, riot.
1.?the act ofdisturbing.
2.?the state of beingdisturbed.
3.?an instance of this; commotion.
4.?something thatdisturbs.
5.?an outbreak of disorder; a breach of public peace:
Political disturbances shook the city.
6.?Meteorology.any cyclonic storm or low-pressure area, usually a small one.
7.?Geology.a crustal movement of moderate intensity, somewhat restricted in area.
EG..And they are writing a tell-all story or causing some kind ofdisturbance, be it legal or whatever else to get attention.
The man was a member of the Los Angeles police force investigating adisturbanceat such-and-such and address.
one wave crest
noun
1.?the highest part of a hill or mountain range; summit.
2.?the head or top of anything.
3.?a ridge or ridgelike formation.
4.?the foamy top of a wave.
EG..His black hair sweeps back from thecrestof his high forehead and laps at the nape of his neck; his lips are pursed.
foam noun
1.?a collection of minute bubbles formed on the surface of a liquid by agitation, fermentation, etc.:
foam on a glass of beer.
foamy adj
infrared
noun?
D: the part of the invisible spectrum that is contiguous to the?red?end of the visible spectrum and that comprises electromagnetic radiation of wavelengths from 800 nm to 1 mm.
牛頓第一定律：the real effect of a force is always to change the speed of a body rather than just to set it moving, whenever a body is not acted on by any force, it will keep on moving in a straight line at the same speed. 力的真正效應(yīng)總是改變物體的速度彬向，而不是僅僅使之運動，只要一個物體沒有收到外力丛肢，它就會以相同的速度保持直線運動颂龙。
牛頓第一運動定律，簡稱牛頓第一定律绘迁。又稱慣性定律嘴秸、惰性定律毁欣。常見的完整表述：任何物體都要保持勻速直線運動或靜止?fàn)顟B(tài)售担，直到外力迫使它改變運動狀態(tài)為止。
牛頓第二定律：the body will accelerate at a rate that is proportional to the force 物體被加速署辉，其改變率與所受外力成正比族铆。
牛頓第二運動定律的常見表述是：物體加速度的大小跟作用力成正比，跟物體的質(zhì)量成反比哭尝，且與物體質(zhì)量的倒數(shù)成正比哥攘；加速度的方向跟作用力的方向相同。
引力定律：every body attracts every other body with a force that is proportional to the mass of each body 任何兩個物體都相互吸引材鹦，其引力大小與每個物體的質(zhì)量成正比逝淹。
the farther apart the bodies, the smaller the force?物體之間的距離越遠，則引力越小
牛頓的普適的萬有引力定律表示如下：任意兩個質(zhì)點有通過連心線方向上的力相互吸引桶唐。該引力大小與它們質(zhì)量的乘積成正比與它們距離的平方成反比栅葡，與兩物體的化學(xué)組成和其間介質(zhì)種類無關(guān)。
沒有絕對的靜止尤泽，靜止是相對的概念欣簇，因而人們無法確認在不同時間發(fā)生的兩個事件是否發(fā)生在空間的同一位置。
Generally, people think time was completely separate from and independent of space.
Although our apparently commonsense notions work well when dealing with things like apples, or?planets that travel comparatively slowly, they don’t work at all for things moving at or near the speed of light.
通常人們認為時間相對于空間是完全分開并且獨立的坯约。經(jīng)典力學(xué)中的其中一個假定是時間和空間是絕對的熊咽，長度和時間間隔的測量與觀測者的運動無關(guān)，物質(zhì)間相互作用的傳遞是瞬時到達的闹丐，由此可知横殴，經(jīng)典力學(xué)實際上只適用于與光速相比低速運動的情況。在高速運動情況下卿拴，時間和長度不能再認為與觀測者的運動無關(guān)衫仑。
麥克斯韋方程預(yù)言
① there could be wavelike disturbances in the combined electromagnetic field, and that these would travel at a fixed speed, like ripples on a pond.在合并的磁場中可以存在波動的微擾，它們以固定的速度堕花，如同池塘水面上的漣漪那樣運動文狱。
②radio or light waves should travel at a certain fixed speed 無線電波或光波應(yīng)該以某一固定的速度運動。
既然擺脫了絕對靜止的概念航徙，也就是說固定的速度必須要有一個參照物才能測量出來如贷，聲波在空氣中傳播陷虎，所以人們認為光在真空中應(yīng)該也是通過一種物體傳播到踏，將之命名為以太。但邁克爾遜－莫雷實驗否定了以太的存在尚猿。愛因斯坦提出拋開絕對時間觀念的話窝稿，整個以太的觀念則是多余的。
the laws of science should be the same for all freely moving observers, no matter what their speed.
相對論的基本假設(shè)：不管觀察者以任何速度做自由運動凿掂，相對于他們而言伴榔，科學(xué)定律都應(yīng)該是一樣的纹蝴。將這個觀念擴展到馬克斯韋理論和光速中，即為不管觀察者運動多快踪少，他們測量出的光速應(yīng)該都是一樣的塘安。
As an object approaches the speed of light, its mass rises ever more quickly, so it takes more and more energy to speed it up further. It can in fact never reach the speed of light, because by then its mass would have become infinite, and by the equivalence of mass and energy, it would have taken an infinite amount of energy to get it there. For this reason, any normal object is forever confined by relativity to move at speeds slower than the speed of light.
當(dāng)一個物體接近光速的時候，它的質(zhì)量上升的越來越快援奢，所以需要越來越多的能量才能進一步加速兼犯。事實上，它永遠都不可能達到光速集漾，因為那時候質(zhì)量會變成無限大切黔，根據(jù)質(zhì)量能量等價原理，所需要的能量也就無限大具篇。所以相對論限制任何正常物體永遠以低于光速的速度運動纬霞。
speed= distance/time
在牛頓理論中，時間是絕對的驱显，空間不是絕對的（time is absolute,space is not absolute）, 所以不同的觀察者就會測量出不同的光速诗芜，所以相對論終結(jié)了（put an end to）絕對時間的概念（absolute time）。
Each observer could use radar to say where and when an event took place by sending out a pulse of light or?radio waves.
準(zhǔn)確測量距離的方法埃疫，記錄發(fā)出脈沖和接受脈沖之間的時間t绢陌，所要測定的對象的距離為 t/2 乘以光速。
The theory of relativity does, however, force us to change fundamentally our ideas of space and time. We must?accept that time is not completely separate from and independent of space, but is combined with it to form an?object called space-time
相對論使我們從根本上改變了對時間和空間的觀念：時間不能完全脫離和獨立于空間熔恢，而必須和空間結(jié)合在一起形成所謂的時空脐湾。
