两个人用力推一辆熄火的小汽车,每个人用力的大小都是200 N,方向都与车的运动方

题型:计算题

问题:

两个人用力推一辆熄火的小汽车,每个人用力的大小都是200 N,方向都与车的运动方向成30°夹角.当推车前进了20 m时,汽车发动机点火起动,求:  

(1)在推车的过程中,两个人对车一共做了多少功?

(2)两个人应该怎样推车,才会达到最好的效果?

考点:牛顿运动定律的应用
题型:计算题

判断下列说法,正确的打“√”,错误的打“×”。     

1.《鸟鸣涧》是唐代诗人白居易的作品。(  )     

2.罗斯福当了十二年美国总统。(  )     

3.第一次登上月球的是阿姆斯特朗等人,时间是1996年7月16日。(  )     

4.孔子采取“因材施教”和“有教无类”的教学方针,受到了学生的敬重。(  )     

5.《中国结》一文表面上写的是中国结,实际上表达的是中华各族儿女对祖国深深的热爱之情。(  )

6.《飞夺泸定桥》一文围绕“飞”和“夺”展开故事情节。(  )

题型:计算题

下面各组句子中,加点词的意义与用法相同的一项是(3分)              (   )

A.①以勇气闻于诸侯               ②严大国之威以修敬也

B.①不如因而厚遇之               ②因厚赂单于

C.①顾召赵御史书日               ②相如虽驽,独畏廉 * * 哉?顾吾念之……

D.①见犯乃死,重负国             ②信义安所见乎

题型:计算题



Americans have four primary avenues for making friends: at work, at school, through a hobby or a (1) such as volunteer work and discussion group, or through a family or (2) .
In American culture, a job is more than the work that one performs between the hours of 9 a.m. and (3) . Work becomes a major socializing influence. Many young mothers who (4) their jobs to care for small children remark on the loneliness of their new lifestyles because they have lost their forum for (5) .
A great number of American employers recognize business social (6) and use it to build a family atmosphere on the job so that employees will feel (7) in their work environment. Some employers arrange company get-togethers in their home or at a (8) . American companies have at least one (9) annually, usually at Christmas time. Many corporations have (10) where employees and administrators alike dress (11) to play games such as baseball and volleyball.
Top American administrators often hold social gatherings (12) . Depending upon the size of the employer’s home and the number of (13) . These social gatherings may be picnics, pool parties, or (14) . If the company is large, an employer may hold what Americans call (15) . For an open house, the employer will invite his employees to come to his home (16) between 1 p.m. on a certain day. Those invited usually stay for (17) , chatting with the other guests and their host. People come and go (18) during the designated hours, and the host keeps refreshments, usually (19) or hors d’oeuvres and beverages, available for all who come. For such social gatherings, it is considered (20) the invitation unless you have an excellent reason.

题型:计算题

中队执勤人员听到出动信号后,必须迅速登车,由()宣布车车命令。

A、执勤队长

B、执勤班长

C、执勤电话员

D、执勤司机

题型:计算题

生产的四要素指的是()、()、原材料和方法。

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