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问题 多选题

如图所示，质量为1kg的物块放在倾角为37°的固定斜面上，若用一平行于斜面的力F推物块，物块和斜面保持静止，斜面与物块之间的最大静摩擦因数μ=0.5，重力加速度g取10m/s2，则外力F的大小可能为（　　）

A．1N

B．6N

C．9N

D．12N

答案

物体重力的沿斜面向下的分力为：

G1=mgsin37°=10×0.6=6N；

垂直于斜面的分力为：

G2=mgcos37°=8N；

则最大静摩擦力为：

Fm=μFN=μG2=0.5×8=4N

若推力向上，由共点力的平衡条件可知，推力最小值为等于重力沿斜面向下的分力；故F=6N；此时静摩擦力为零；

增大推力后，摩擦力变大，当达到最大静摩擦力时，推力最大为F′m=4+6=10N；

而当推力向下时，最大静摩擦力小于重力的分力，物体不可能处于静止状态；

故外力最大为10N，最小为6N；

故BC正确；

故选：BC．

阅读理解

阅读下列应用文及相关信息，并按照要求匹配信息。请在答题卡上将对应题号的相应选项字母涂黑。(注意：选择答案E时，请在答题卡上同时涂A和B选项；选择答案F时，请在答题卡上同时涂C和D选项。)

Featured phonesA. Nokia-6010Price: ＄24.99        Color display: Yes         Wireless Internet ready: Yes     

Digital camera: No  2-way text messaging: Yes     Talk time: Up to 330 minutes

Standby time: Up to 240 hours       Weight: 5.08 ounces        

Dimensions: 4.68”×1.97”×0.90”

Games: Backgammon, Bowling, Air glide, and Sky diver plus downloadable Java games

B. Motorola-C650 (Camera phone)

Price: ＄99.99     Color display: Yes          Wireless Internet ready: Yes

Digital camera: Yes  2-way text messaging: Yes  Talk time: Up to 210 minutes

Standby time: Up to 215 hours   Weight: 3.10 ounces

Games:Downloadable games

C. Samsung-V1660 on Sprint PCSPrice: Free         Color display: Yes          Wireless Internet ready: Yes

2-way text messaging: Yes   Talk time: Up to 204 minutes   

Standby time: Up to 168 hours

Weight: 3.54 ounces             Memory locations: 200 entry phonebook

D. Motorola-SLVR-L7Price: ＄206.4      Color display: Yes          Wireless Internet ready: Yes

Digital camera: Yes 2-way text messaging: Yes   Talk time: Up to 450 minutes

Standby time: Up to 345 hours       Weight: 3.39 ounces        

Dimensions: 4.45”×1.93”×0.45”

Games: Enjoy pre-loaded J2ME games or downloadable games

E. Nokia-8010Price: ＄124.99     Color display: Yes          Wireless Internet ready: Yes

Digital camera: No  2-way text messaging: Yes   Talk time: Up to 330 minutes

Standby time: Up to 240 hours       Weight: 4.08 ounces        

Dimensions: 3.68”×1.27”×0.70”              Games: Downloadable games

F. Kyocera-SE47 slider滑块 on venison wirelessPrice: ＄149.99     Color display: Yes      Wireless Internet ready: Yes

Digital camera: No  2-way text messaging: Yes  Talk time: Up to 210 minutes

Standby time: Up to 100 hours       Weight: 3.39 ounces           

Memory locations: 200 entry phonebook

阅读下面信息介绍，并按照要求匹配信息。首先，请阅读下列信息：

小题1:Susan is at a middle school. Her parents want to buy her a cheaper cellphone without games installed.

小题2:Mike intends to buy a phone with longer talk time and standby time and it must not be expensive.

小题3:Jane is at college. She would like to buy a phone which can slide(滑开) the face up to make a call, and slide it down when you’re done and it has to be light.

小题4:George would like to have a cheaper phone with digital camera.

小题5:Tom only buys Nokia. He lost one and he wants to buy another which is smaller.
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单项选择题

全党要增强紧迫感和责任感，牢牢把握加强党的执政能力建设、先进性和（）建设这条主线。

A.制度

B.作风

C.纯洁性
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