有些航空母舰上装有帮助飞机起飞的弹射系统,已知某型号的战斗机在跑道上加速时可能产

题型:计算题

问题:

有些航空母舰上装有帮助飞机起飞的弹射系统,已知某型号的战斗机在跑道上加速时可能产生的最大加速度为5.0 m/s2,当飞机的速度达到50 m/s时才能离开航母起飞,设航母处于静止状态,问:

(1)若要求该飞机滑行160 m后起飞,弹射系统必须使飞机具有多大的初速度?

(2)若某舰上不装弹射系统,要求该型号飞机仍能在此舰上正常起飞,问该舰身长至少应为多长?

考点:匀变速直线运动的位移与速度的关系
题型:计算题

目前我国证券市场推出的权证均为债券类权证,其标的资产可以是单只债券或债券组合。()

题型:计算题

小强乘坐从上海开往泉州的动车,当动车进入泉州境内时他感慨地说:“我终于来到泉州了!”,他说出这句话时所选择的参照物是

A.泉州

B.小强本人

C.小强所乘坐的动车

D.坐在小强身边的乘客

题型:计算题

结构试验时,固定铰支座可以使用于()。

A.连续梁结构的一端

B.简支梁的两端

C.悬臂梁结构的一端

D.柱或墙板构件的两端

题型:计算题

Shopping has always been something of an impulse activity, in which objects that catch our fancy while strolling are immediately bought on a whim. Advertisers and sellers have taken advantage of this fact, carefully positioning inexpensive but attractive items on paths that we are most likely to cross, hoping that our human nature will lead to a greater profit for them. With the dawn of the Internet and its exploding use across the world, the same tactics apply.

Advertisers now place "banners", links to commercial web sites decorated with attractive pictures designed to catch our eyes while browsing the webs, on key web sites with heavy traffic. They pay top dollar for the right, thus creating profits for the hosting web site as well. These actions are performed in the hopes that during the course of our casual and leisurely web surfing, we’ll click on that banner that sparks our interest and thus, in theory, buy the products advertised.

Initial results have been positive. Web sites report a huge inflow of cash, both from the advertisers who tempt customers in with the banners and the hosting web sites, which are paid for allowing the banners to be put in place. As trust and confidence in Internet buying increases and information security is heightened with new technology, the volume of buying is increasing, leading to even greater profits.

The current situation, however, is not quite as optimistic. Just as magazine readers tend to unconsciously ignore advertisements in their favorite periodicals, web browsers are beginning to allow banners to slip their notice as well. Internet users respond to the flood of banners by viewing them as annoyances, a negative image that is hurting sales, since users are now less reluctant to click on those banners, preferring not to support the system that puts them in place. If Internet advertising is to continue to be a viable and profitable business practice, new methods will need to be considered to reinvigorate the industry.

With the recent depression in the technology sector and slowing economy, even new practices may not do the trick. As consumers are saving more and frequenting traditional real estate businesses over their Internet counterparts, the fate of Internet business is called into question. The coming years will be the only reliable indication of whether shopping on the World Wide Web is the wave of the future or simply an impulse activity whose whim has passed. (404 words)

Notes: on a whim 心血来潮。surf v.冲浪。in theory在理论上,顺理成章。hosting 访问率离的。call...into question 质疑,对……提出疑问。

It can be learned from the first paragraph that Internet advertising()

A. has taken the place of more traditional methods of advertising

B. is one of the most effective ways to make profits on the web

C. is paralleling advertising methods in traditional business settings

D. seeks to tempt customers through impulse shopping methods

题型:计算题

用力法计算,校核最后内力图时只要满足平衡条件即可。

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