问题 多选题

如图,一木块放在水平桌面上,在水平方向共受到三个力即F1、F2和摩擦力作用.木块处于静止状态.其中F1=10N、F2=4N.以下判断正确的是(  )

A.若撤去力F1,则木块在水平方向受到的合力可能为2N

B.若撤去力F1,则木块在水平方向受到的合力可能为0

C.若撤去力F2,则木块在水平方向受到的合力可能为2N

D.若撤去力F2,则木块在水平方向受到的合力可能为0

答案

一木块放在水平桌面上,在水平方向共受到三个力即F1、F2和摩擦力作用.木块处于静止状态.根据平衡知,静摩擦力的大小为f=6N,知最大静摩擦力大于等于6N.

A、撤去力F1,因为F2=4N,小于最大静摩擦力,知木块仍然处于静止状态,所受的合力为零.故A错误,B正确.

B、若撤去力F2,因为F1=10N,因为最大静摩擦力大于等于6N,若物体开始滑到,滑动摩擦力为8N,则合力为2N.若最大静摩擦力大于10N,物块仍然静止,则合力为零.故C、D正确.

故选BCD.

单项选择题
阅读理解

阅读理解:信息匹配。

_____1. His platinum albums such as "You Make Me Happy and Sad," "Flowery Heart," "Music Brings Us

Together" and "Emil & Friends" have brought him numerous awards in Singapore, and China's Taiwan and

Hong Kong.

_____2. Jonathan Lee represents the creative spirit of the past 20 years in Taiwan and many renowned singers

like Sarah Chan (Chen Shuhua), Sandy Lam (Lin Yilian), Emil Chau (Zhou Huajian) and Karen Mok (Mo

Wenwei) draw great inspiration from Lee's works.

_____3. Jasmine Leong is a Malaysian singer who is very popular on the Taiwan music scene. Focusing on

lyrical songs, Leong's Beijing performance will also tap into rock & roll music.

_____4. To remember Henrik Ibsen, with pianist Wolfgang Plagge, violinist Annar Folles and soprano Gao

Xia, the Norwegian Ibsen Trio will present the classic works of the celebrated playwright.

_____5. The mix of musical treats for children in Beijing includes various kinds of art forms, including

Western classical music and Chinese traditional music, as well as puppet plays, crosstalk shows, and highlights

of Chinese local operas such as Peking Operas and Kunqu Operas.

A. Commemorative show: To mark the 100th anniversary of the birth of Norwegian playwright Henrik Ibsen,

     the founder of modern prose drama, a concert titled "Nora's Songs" will be given.

     Time: 7:30 pm, March 20

     Place: Peking University Concert Hall

     Tel: 6275-2279, 6275-9637

B. Feel the mood: Jonathan Lee will host his 2006 concert in Beijing. As the master of music in Taiwan, Lee is

     famous for his unique annotation of love, mood and life.

     Time: 7:30 pm, March 24, 25

     Place: Capital Gymnasium, Baishiqiao Lu, Haidian District

     Tel: 6835-4020

C. Chamber music: The chamber concert series of China Philharmonic Symphony Orchestra will greet

     audiences with a woodwind quintet, a string quartet plus Bach's piano concerto and suite.

     Time: 7:30 pm, March 25

     Place: The Concert Hall of the Central Conservatory of Music, 43 Baojiajie, Xicheng District

     Tel: 6641-4759, 6642-5744

D. Pop star: Singer and composer Emil Chau, one of the most admired music idols in China and Southeast

     Asia, will perform a solo concert in Beijing. Chau was born in Hong Kong and attended college in Taiwan.

     He has released more than 30 albums in Mandarin, Cantonese and English.

     Time: 7:30 pm, March 31

     Place: Capital Gymnasium, Baishiqiao Lu, Haidian District

     Tel: 6833-5552

E. Music for children: Some 50 colourful music-related performances will be staged until August 28 in an

    "Open the Door to Music" series of concerts, in a move to foster Chinese children's taste for art. The

     concert series will be held in several venues, sponsored by the Forbidden City Concert Hall and supported

     by the Beijing Municipal Culture Bureau.

     Tickets: 10-100 yuan (US$1-12)

     Time/date: 2 pm or 7:30 pm, July 20-August 28

     Location: mainly in the Forbidden City Concert Hall in Zhongshan Park, some in Peking University Hall in

     Haidian District and in the China Puppet Art Theatre and Poly Theatre

     Tel: 6506-5343, 6506-5345

F. Beautiful timbre: Jasmine Leong will meet her Beijing fans next month. Singing with beautiful timbre, Leong

     will present a series of love stories to the audience. To highlight the theme of love, 200 sets of lover's

     tickets, valued at 1800 yuan will be presented.

     Tickets: 180-980 yuan (US$22-121)

     Time/date: 7:30 pm, September 9

     Location: Workers' Gymnasium, Gongti Beilu, Chaoyang District Tel: 6501-6655