比一比． 84982八八______k65432八八 k35万______k35

(12分)一个不带电的金属板，表面有很薄的光滑绝缘层，与水平方向成θ角放置.金属板上B、C两点间的距离为L，在金属板上方的A点固定一个带电荷量为+Q的点电荷，金属板处在+Q的电场中.已知A、B、C三点在同一竖直平面内，且AB水平，AC竖直，如图所示.将一个带电荷量为+q(q Q，q对原电场无影响)可看做点电荷的小球，从B点无初速释放，如果小球质量为m，下滑过程中带电荷量不变，求：

(1)小球在B点的加速度；

(2)下滑到C点时的速度.

根据下面的装置图回答问题：

（1）写出有标号的仪器的名称：①______ ②_______

（2）第一小组采用过氧化氢溶液和二氧化锰来制取并收集比较纯净的氧气，他们选择的装置组合为________，反应的文字表达式为_________。实验中他们发现反应速率太快而来不及收集，为此他们想选择一种仪器来添加液体以达到平稳的氧气流，你认为他们选择的仪器可能是________（填序号）。

[供选择的仪器：①长颈漏斗、②分液漏斗（带活塞）③漏斗④针筒]

（3）第二小组采用加热氯酸钾和二氧化锰的混合物来制取氧气，他们选择的发生装置为________，制取主要步骤有： ①固定装置 ②装入药品 ③加热 ④检查装置的气密性 ⑤用排水法收集 ⑥熄灭酒精灯 ⑦从水槽中移出导气管。其操作顺序是_________，反应的文字表达式为_________，该实验中试管口应略向下倾斜的原因是__________。

（4）实验室制取H₂是用固态的锌粒和液态的稀硫酸在常温下反应进行的，应选用发生装置是_______（填写装置序号），可以用C或E装置收集H₂，说明H₂具有_________、________等性质。

甲同学想知道花生与核桃哪个含的能量多。为此，他进行了如下的实验，两个小锥形瓶装入同样高度的水，取一个花生仁、半个核桃仁，在酒精灯上点燃后，分别放在小锥形瓶下，给水加热。等花生仁、核桃仁燃烧完毕，分别测出两个小锥形瓶中水的温度。再经过换算，得出结论。请问，甲同学的根据实验结果作出的结论准确吗？为什么？

Required:

(b) Jocatt operates in the energy industry and undertakes complex natural gas trading arrangements, which involve exchanges in resources with other companies in the industry. Jocatt is entering into a long-term contract for the supply of gas and is raising a loan on the strength of this contract. The proceeds of the loan are to be received over the year to 30 November 2011 and are to be repaid over four years to 30 November 2015. Jocatt wishes to report the proceeds as operating cash flow because it is related to a long-term purchase contract. The directors of Jocatt receive extra income if the operating cash flow exceeds a predetermined target for the year and feel that the indirect method is more useful and informative to users of financial statements than the direct method.(i) Comment on the directors’ view that the indirect method of preparing statements of cash flow is more useful and informative to users than the direct method. (7 marks)(ii) Discuss the reasons why the directors may wish to report the loan proceeds as an operating cash flow rather than a financing cash flow and whether there are any ethical implications of adopting this treatment. (6 marks)Professional marks will be awarded in part (b) for the clarity and quality of discussion. (2 marks)

什么叫第一宇宙速度、第二宇宙速度、第三宇宙速度？它们分别是多少？