不管什么类型的高炉，炮泥愈硬愈好。

半径为R的光滑绝缘半球槽处在水平向右的匀强电场中，一质量为m的带电小球从槽的右端A处（与球心等高）无初速度沿轨道滑下，滑到最低点B时，球对轨道的压力为2mg．求：

（1）小球从A到B的过程中电场力做的功及电场力的大小；

（2）带电小球在滑动过程中的最大速度．

女性，34岁，近2年来无诱因下出现头痛头昏，清晨起床时明显，常伴有恶心、呕吐。

为确定病因，应首选的检查是（）

A.MRI

B.EEG

C.脑血管造影

D.CT

E.腰椎穿刺

Doc, a supplier of building materials, entered into the following transactions:(a) An agreement to sell some goods to a longstanding friend, Ed. The contractual document, however, actually stated that the contract was made with Ed’s company, Ed Ltd. Although the materials were delivered, they have not been paid for and Doc has learned that Ed Ltd has just gone into insolvent liquidation. (4 marks)(b) Doc had employed a salesman, Fitt, whose contract of employment contained a clause preventing him, Fitt, from approaching any of Doc’s clients for a period of two years after he had left Doc’s employment. Doc has found out that, on stopping working for him, Fitt has started working for a company, Gen Ltd, wholly owned by Fitt and his wife, and is approaching contacts he had made while working for Doc. (6 marks)Required:In the context of company law, advise Doc as to the legality and likely outcome of the above situations.Notes:– in (b) the legality of the restraint of trade clause in Fitt’s contract of employment may be assumed; and– the mark allocation is shown against each of the transactions above. (10 marks)

《古怪的姓》中，小青蛙帮磨坊老板的女儿把麦秆纺成金子。

简述不合理开发矿产资源引起的环境问题。