【正文】 隨著地理位置的變化變化沒有方向方向豎直向下聯(lián)系 G ＝ m g力和運(yùn)動知識點總結(jié)1慣性：物體保持運(yùn)動狀態(tài)不變的必質(zhì)，叫慣性。(物體保持靜止?fàn)顟B(tài)或勻速直線運(yùn)動狀態(tài)不變的性質(zhì)。)因此牛頓第一運(yùn)動定律又叫慣性定律。2力的平衡：物體在受到幾個力的作用時，如果保持靜止?fàn)顟B(tài)或勻速直線運(yùn)動狀態(tài)，我們就說這幾個力相互平衡。3二力平衡的條件：作用在一個物體上的兩個力，如果大小相等，方向相反并且在同一直線上，這兩個力就彼此平衡。(大小相等，方向相反，同一物體，同一直線)4摩擦力：在接觸面上產(chǎn)生的阻礙物體相對運(yùn)動的力5影響滑動摩擦力大小的因素：（1）壓力的大小。（2）接觸面的粗糙程度。6增大摩擦的方法：（1）使接觸面更粗糙。（2）增大壓力。7減小摩擦的方法：（1）使接觸面更光滑。（2）利用滾動代代替滑動（3）使接摩擦面脫離接觸，即使用潤滑油或氣墊。機(jī)械能知識點總結(jié)判斷一個物體是否具有能的標(biāo)準(zhǔn)是：物體能夠做功，我們就說它具有能 2 動能：物體由于運(yùn)動而具有的能。它的大小決定于物體的質(zhì)量和運(yùn)動速度重力勢能：物體由于被而具有的能量。它的大小決定于物體的質(zhì)量和被舉彈性勢能：物體由于發(fā)生了彈性形變而具有的能。其大小決定于物體的彈性形變量。機(jī)械能：動能和勢能統(tǒng)稱機(jī)械能。機(jī)械能的轉(zhuǎn)化和守恒定律：動能可以轉(zhuǎn)化為勢能，勢能可以轉(zhuǎn)化為動能，在機(jī)械能的相互轉(zhuǎn)化過程中，機(jī)械能的總量保持不變。一般認(rèn)為地球表面為勢能零點，也可認(rèn)為是物體所能運(yùn)動到的最低點。比如分析飛燕的能量，分析石子向上拋的再下落的過程中能的轉(zhuǎn)化內(nèi)能知識點總結(jié)分子運(yùn)動論：物質(zhì)是由分子組成的；分子永不停息地做無規(guī)則運(yùn)動；分子間存在著相互作用的引力和斥力。擴(kuò)散：相互接觸的不同物質(zhì)，彼此進(jìn)入對方的現(xiàn)象。分子間作用力大?。寒?dāng)分子間距大于平衡位置時，引力起主要作用；當(dāng)分子間距小于平衡位置時，斥力起主要作用。內(nèi)能：物體內(nèi)部所有分子做無規(guī)則運(yùn)動的動能和分子勢能的總合。(熱能)5 影響內(nèi)能大小的因素：溫度。內(nèi)能越大溫度越高，內(nèi)能越小溫度越低6熱運(yùn)動：物體內(nèi)部大量分子的無規(guī)則運(yùn)動。叫熱運(yùn)動。內(nèi)能與機(jī)械能的不同：機(jī)械能與整個物體的機(jī)械運(yùn)動情況有關(guān)，內(nèi)能與物內(nèi)部分子的熱運(yùn)動和分子間的作用情況有關(guān)。改變內(nèi)能的方法：做功和熱傳遞。熱量：在熱傳遞過程中，傳遞的能量的多少叫做熱量。(發(fā)生熱傳遞的條件是：不同的物體間具有溫度差。)內(nèi)能與做功：物體對外做功，內(nèi)能減小，外界對物體做功，物體內(nèi)能增加 11 比熱容：單位質(zhì)量的某種物質(zhì)溫度升高1℃吸收的熱量。熱平衡方程：Q=Cm△t Q吸=Cm(tt0)Q放=Cm(t0t)無熱損時Q吸=Q放 13 能量守恒定律：能量既不會消滅也不會創(chuàng)生，它只會從一種形式轉(zhuǎn)化為另一種形式，或者從一個物體轉(zhuǎn)移到另一個物體，而在轉(zhuǎn)化和轉(zhuǎn)移的過程中，能量的總量保持不變。熱機(jī)知識點總結(jié)燃料的燃燒值：1千克的某種燃燒完全燃燒放出的熱量，叫這種燃料的熱值 2 爐子的效率：爐子的有效利用熱量與燃料完全燃燒放出的熱量之比。3 燃燒時能量的轉(zhuǎn)化：化學(xué)能轉(zhuǎn)化為內(nèi)(熱)能。內(nèi)能的兩個基本應(yīng)用：加熱和做功。內(nèi)燃機(jī)的工作原理：汽油或柴油在氣缸內(nèi)燃燒，生成高溫高壓燃?xì)?，燃?xì)庠偻苿踊钊龉?。?nèi)燃機(jī)的四個沖程：吸氣沖程、壓縮沖程、做功沖程和排氣沖程。做功沖程又叫燃燒－膨脹做功沖程。在內(nèi)燃機(jī)中，一個工作循環(huán)飛輪轉(zhuǎn)兩圈，活塞四個沖程。即1:2:4沖程：在活塞的往復(fù)運(yùn)動中，它從氣缸的一端運(yùn)動到另一端就叫做一個沖程。內(nèi)燃機(jī)的工作過程：在吸氣沖程中，活塞向下移動，同時進(jìn)氣門打開，吸進(jìn)汽油和空氣組成的燃?xì)?；在壓縮沖程中，進(jìn)氣門和排氣門都關(guān)閉，活塞向上運(yùn)動，燃料的混合物被壓縮，壓強(qiáng)增大溫度升高；在做功沖程中，火花塞產(chǎn)生電火花，使燃料猛烈燃燒，產(chǎn)生高溫高壓燃?xì)?，高溫高壓燃?xì)馔苿踊钊蛳逻\(yùn)動，并通過連桿帶動曲軸轉(zhuǎn)動；在排氣沖程中，進(jìn)氣門仍關(guān)閉，排氣門打開，活塞向上運(yùn)動，把廢氣排出氣缸汽油機(jī)和柴油機(jī)的不同：1吸氣沖程中，吸進(jìn)的工作物質(zhì)不同，汽油機(jī)吸進(jìn)的是汽油和空氣的混合物，而柴油機(jī)吸進(jìn)的是空氣。2 有結(jié)構(gòu)上汽油機(jī)氣缸頂是火花塞，而柴油機(jī)是噴油嘴。3在工作方式上，汽油機(jī)采用用火花塞的點燃式工作方式，柴油機(jī)采用壓燃式工作方式。9熱機(jī)的效率:用來做有用功的那部分能量和燃料完全燃燒放出的能量之比第五篇：物理專業(yè)英語緒論IntroductionPhysics is a natural science that involves the study of matter and its motion through spacetime(時空), as well as all applicable concepts, such as energy and broadly, it is the general analysis of nature, conducted in order to understand how the world and universe is one of the oldest academic disciplines(學(xué)科), perhaps the oldest through its inclusion of the last two millennia(一千年), physics had been considered synonymous with philosophy, chemistry, and certain branches of mathematics and biology, but during the Scientific Revolution in the 16th century, it emerged(顯現(xiàn))to bee a unique modern science in its own , in some subject areas such as in mathematical physics and quantum chemistry, the boundaries of physics remain difficult to is both significant and influential, in part because advances in its understanding have often translated into new technologies, but also because new ideas in physics often resonate(共鳴)with other sciences, mathematics, and example, advances in the understanding of electromagnetism(電磁學(xué))or nuclear physics led directly to the development of new products which have dramatically transformed modernday society。advances in thermodynamics(熱力學(xué))led to the development of motorized transport。and advances in mechanics(力學(xué))inspired the development of and aimsPhysics covers a wide range of phenomena,from the smallest subatomic particles, to the largest aims to describe the various phenomena that occur in nature in terms of simpler , physics aims to both connect the things observable to humans to root causes, and then to try to connect these causes together in the hope of finding an ultimate reason for why nature is as it example, the ancient Chinese observed that certain rockswere attracted to one another by some invisible effect was later called magnetism, and was first rigorously studied in the 17th little earlier than the Chinese, the ancient Greeks knew of other objects such as amber, that when rubbed with fur would cause a similar invisible attraction between the was also first studied rigorously in the 17th century, and came to be called , physics had e to understand two observations of nature in terms of some root cause(electricity and magnetism).However, further work in the 19th century revealed that these two forces were just two different aspects of one force – scientific methodPhysicists use the scientific method to test the validity(認(rèn)可)of a physical which are very well supported by data and have never failed any petent empirical(以實驗為依據(jù)的)test are often called scientific laws, or natural course, all theories, including those called scientific laws, can always be replaced by more accurate, generalized statements if a disagreement of theory with observed data is ever found.