在测定匀变速直线运动的实验中,打点计时器打出一纸条,每隔四个点选出一个计数点共选

题型:实验题

问题:

在测定匀变速直线运动的实验中,打点计时器打出一纸条,每隔四个点选出一个计数点共选出A、B、C、D四个计数点,所用交流电频率为50赫兹,纸带上各点对应尺上的刻度如图所示,则:

17小题1:如果使用电火花打点计时器,则应使用的电源是:(    )

A.4-6伏直流电

B.4-6伏交流电

C.220伏直流电

D.220伏交流电18小题2:纸带上选出的B、C两点间的时间间隔为:(    )

A、0.02s         B、0.08s 

C、0.1s          D、0.2s

19小题3:纸带上B点的速度大小为:(     )

A.0.064 m/s

B.0.15 m/s

C.0.3m/s

D.0.4m/s20小题4:纸带记录的匀变速直线运动的加速度大小为:(    )

A.0.2 m/s2

B.1.4 m/s2

C.2.0 m/s2

D.6.4 m/s2

考点:实验:探究弹力与弹簧伸长的关系实验:探究小车速度随时间变化的规律实验:探究加速度与力、质量的关系实验:探究功与速度变化的关系
题型:实验题

Complete the following passage by filling in each blank with one word that best fits the context.

On November 2nd San Francisco became the first major US city to pass a law on controlling give-away toys with unhealthy restaurant meals marketed at kids.

小题1:______law will take effect on December 1, 2011. It is required that kids’ meals

小题2: 

      meet certain nutritional standards 小题3:      they can be sold with free toys.

McDonald’s officials were angry with the decision,小题4:      effectively bans their popular Happy Meals.

But supporters say小题5:      aims to promote healthy habits while combating child obesity(肥胖). “This is a challenge to the restaurant industry to think about children’s health first,” said San Francisco Supervisor Eric Mar.

About 15 percent of American 小题6:           are overweight or obese, which puts them 小题7:      risk of developing heart disease, cancer, etc. In some states, the childhood obesity rate is over 30 percent.

McDonald’s started to sell the Happy Meals in 1979 with toys. In 2006, fast-food companies spent more than $520 million on advertising and toys to promote meals 小题8: children, according to the US government.

题型:实验题

有以下程序 intā*f(int*x,int*y) { if(*x<*y) return x; else return y; } main( ) { int a=7,b=8,*p,*q,*r; p=&a;q=&b; r=f(p,q); cout<<*p<<","<<*q<<","<<*r<<endl; } 执行后输出结果是

A.7,8,8

B.7,8,7

C.8,7,7

D.8,7,8

题型:实验题

轮廓线可以用细实线来表示。

题型:实验题

在教育起源问题上,认为教育的产生完全来自动物本能的观点是()。

A.生物起源说

B.神话起源说

C.心理起源说

D.劳动起源说

题型:实验题

某慢性肾小球肾炎患者,近几天见血尿明显,水肿加重,BP182/105mmHg,根据该患者病情,护士制定的休息原则应为

A.劳逸结合
B.保证睡眠
C.适当休息
D.卧床休息
E.增加休息

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