年級

問題的種類

英文 高中

第四段第二行的pack是什麼意思? 解答寫「電池」但是我查不到pack有這個意思

第31至35 題為題組 Since the early 1990s, the hihilin zion battery has been the most suitable battery for portation to y 31 electronic equipment. Today, they're commonly used for cellphones, computers, tablets, digital cameras, and other devices. Lithium-ion batteries have nearly twice the energy density of traditional nicket cadmium batteries. 31 This feature has important implications for cellphones and computers, because it makes these items more portable for consumers. It also makes power tools easier to use and allows workers to use them for longer periods of time, 32. 32 Lithium-ion batteries retain retain mo naman of their power capacity from previous charging cycles. Thus they require no scheduled cycling and can be fully re-fueled to their maximum capacity during each charging cycle. Other rechargeable battery types, in contrast, retain information from previous charging cycles, which wastes valuable storage space. Over time, this makes these rechargeable batteries hold less of a charge. 33 It is fragile and requires a protection circuit to maintain safe operation. A high load could overheat the pack and safety might be jeopardized. 34 F After 2-3 years of use, the pack often becomes unserviceable due to a large voltage drop caused by high internal resistance. It should be noted, however, that manufacturers are constantly making improvements on lithium-ion batteries. 35 With such rapid progress, the use of lithium-ion batteries will certainly expand further. (A (A) The lithium-ion battery is also a low maintenance battery. (B) Despite its overall advantages, the lithium-ion battery has its drawbacks. (C) New and enhanced chemical combinations are introduced every six months or so. (D) Attempts to develop rechargeable lithium-ion batteries failed due to memory problems. (E) That is, they carry more power in a smaller unit, helping to reduce overall weight and size. d (F). Another downside is the increase of the internal resistance that occurs with cycling and aging. -3-

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數學 高中

根本看不懂啦\( ̄▽ ̄;)/

Your report should follow these guidelines, although you may choose how you present it: How to Write a Mathematics Report In writing your report, remember that you are writing up a mathematical story and so, like all good stories, it will need a beginning, a middle and an end. More formally, the main components of this writing style are: Introduction, Formulating the Problem, Solving the problem, Discussion of Results, and Conclusion. We will now consider some of the detail in each of these aspects. Introduction This is the beginning of the story. Give a brief explanation of what the problem is about what the goals of the report are and what will be presented. Assume that your reader does not know what the problem is about or how to solve it. Formulating the problem Translate the situation into a maths problem. Explain how you will begin to solve the problem and break it into simpler stages. Discuss any assumptions made. What quantities are variables and which values are fixed? You may use sub-headings if they assist you. Solving the Problem Show any calculations and mathematical reasoning that you use. (Assume that your reader does not know much maths). Do not show the same types of calculations repetitively. Just give one or two examples of a calculation and then put the rest of the results in a table. Use diagrams or graphs if they assist you. Make general remarks about what you observe in your calculation results and, possibly, why. You may want to criticise your work and go on to improve it in the next section. Explain what you will do next and why. Discussion of Results - Evaluate and Verify Summarise your results if necessary and refer to your mathematical reasoning. Justify procedures used. Interpret your results. First, are they reasonable or does something not look right and need further investigation or checking? Is there a decision to be made? Here is where you should present the decision-making process. Evaluate the strengths and limitations of your solutions. Conclusion Summarise your findings. Refer to the problem outlined in the introduction. Make sure that you answer the question that was asked. Make recommendations. No new material should be presented here.

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自然科學 大學

求解圖裡UICK quiz的第二小題

acit0r 1taneOuls CUrTent Differentiating Equation 27.22 with respectto time gives the inst: as afunction of time: 4 tt號 一Fe ptasafurc 主二 where Q;/有CC 三方 is the initial current. Figure 27.15b 5 in the resistor that we guessedin order to-apply Kirch Equations 27.15 and 27.21. Equation 27.23 shows that the ci ing capacitor is negative, indicating that the current 1s Figure 27.15c. Both the charge on the capacitor and the ct tially at a rate characterized by the time'constant7了三用C. 人 i 一 GOuicK ouiz 27.5 Considerthe circuitin Figure 27.17 and assume the battery has after the switch is closed, what is the currentin the Figure 27.17 no internal resistance. () 」 battery (a) 0 (b) &/2A(G 28/Z04 8/元(e) impossible to determine (ii) After a 有 eyerylong time, what is the Currentin the battery? Choose from the same choices. theswitch is CC (3 前:銜1加信介2放 IntermittentWindshield Wipers nobiles are equipped with windshield wipers that can operate intermittently during alight rainfall. How does ofsuch wipers depend on the charging and discharging ofacapacitor7 民 The wipers are part ofan 及C circuit whose time constant can be varied by selecting different values of及through amultipo- Sition sWitch. As the voltage across the capacitor increases, the capacitor reaches a point at which it discharges and Higgers the wipers. The circuit then begins another charging cycle. The time interval between the individual sweeps of the wiperS 1 determinedjby the value ofthe time constant.

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