如图所示,质量分别为、的A、B两物块用轻线连接放在倾角为的斜面上,用始终平行于斜

题型:选择题

问题:

如图所示,质量分别为的A、B两物块用轻线连接放在倾角为的斜面上,用始终平行于斜面向上的拉力F拉A,使它们沿斜面匀加速上升,A、B与斜面的动摩擦因数均为为了增加轻线上的张力,可行的办法是    (     )

A.减小A物块的质量              B.增大B物块的质量

C.增大倾角                     D.增大动摩擦因数

考点:受力分析
题型:选择题

—Do you know _______?

—At 8:00 a.m.[ ]

A.who to talk with            

B. when to have a meeting

C. what to do next        

D. where to go swimming

题型:选择题

A new system that scans customers’ fingerprints and subtracts(减去)the grocery bill from their bank accounts has taken supermarkets in Germany to use the new system. “Almost a quarter of our customers pay with their fingers,” said an employee at the headquarters. Edeka has tried the system at 70 of its supermarkets. It says it will introduce it at 200 others because customers like it.

“At first we thought that only the young who really keep up with the latest technology would be interested, but we were wrong,” said Stefan Sewoester from IT Werke. “Almost two-thirds of the people who use the system are 40 and older,” he said.

IT Werke, a computer company, is one of the pioneers of fingerprint payment software in Germany. It has helped about 150 shops, canteens and bars to put in the fingerprint scanning machines. Each costs about 2,000 euros.

To sign up for the service, customers must have their fingerprints taken and leave their addresses and banking details with the shop. The shop then takes the cost of goods directly out of the customer’s bank account.

“It is especially a good thing for elderly people. Now they do not have to remember their pin to pay with their bank cards, or to scratch around for their glasses or cash.” Sewoester said.

The stores benefit from the system too. It saves more than time in the check-out line. It also cuts out the hidden costs of accepting electronic card payments.

小题1:According to the passage, the fingerprint system______.

A.was invented by the Edeka supermarket chain

B.has caused payment revolution in Germany

C.is more popular with young people

D.is preferred by most American customers小题2:To apply to pay with fingers, customers are required to do all of the following EXCEPT______.

A.have their fingerprints taken

B.leave their addresses

C.give the shop information about the bank accounts

D.have their phones connected with computers小题3:Why do elderly people benefit much from the fingerprint machine?

A.They will spend less time on shopping..

B.They are not forgetful.

C.They don’t like to pay in cash

D.They always fail to find their bank cards.

题型:选择题

在用万用表判别三极管性能时,若集电极-基极的正反向电阻均很大,则说明该三极管已被击穿。

题型:选择题

结核菌引起儿童发病与否最主要是取决于()

A.结核菌的数量

B.菌群类型

C.结核菌的毒力

D.体液免疫力的强弱

E.细胞免疫力的强弱

题型:选择题

侧壁()

A.Ⅱ、Ⅲ、aVF导联

B.Ⅰ、aVL导联

C.V1、V2、V3导联

D.V3、V4、V5导联

E.V5、V6导联

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