一个小孩从滑梯上滑下的运动可看作是匀加速直线运动,第一次小孩单独滑下,加速度为a

题型:不定项选择

问题:

一个小孩从滑梯上滑下的运动可看作是匀加速直线运动,第一次小孩单独滑下,加速度为a1;第一次小孩背着书包滑下,加速度为a2;则[ ]

A.a1=a2

B.a1>a2

C.a1<a2

D.无法判断

考点:牛顿运动定律的应用
题型:不定项选择

A large number of people in the world eat fast food. Whenever you go into a fast food restaurant, you can see lots of people enjoying their meals there. But do you know in which country people like fast food best?

The English people are the world’s biggest fans of fast food, while the French(法国人) are the least interedted in quick meals, according to a survey done last year.

The servery of thirteen countries shows 45% of the English people say they can’t give up fast food  because it’s delicious. And 44% of Americans and 37% of Canadians say the same.

The French, proud of their delicious and high class cuisine, don’t like fast food. 81% of them think it is unhealthy, followed by 75% of the Japanese.

How about the Chinese? How often do you have hamburgers or fried chicken? It doesn’t matter whether you like western fast food or Chinese food. The most important thing is to keep a balanced diet.

小题1:From the survey we know _________ like fast food best.

A.the Chinese

B.the French

C.the Japanese

D.the English小题2:The survey shows _________ of Americans like fast food.

A.37%

B.44%

C.75%

D.81%小题3:According to the survety, some people can’t give up fast food because ________.

A.it’s cheap

B.it’s safe

C.it’s delicious

D.it’s healthy小题4:_________ people are the world’s biggest fans of fast food.

A.English

B.Chinese

C.American

D.French小题5:The survey is about _________.

A.western countries

B.fast food

C.restaurants in the world

D.Chinese food

题型:不定项选择

托盘天平只能用于粗略的称量,能精确到______g.若某同学用托盘天平称量时,在右盘放称量物,左盘加5g砝码,再把游码移至0.4g处,使天平达到平衡,则该称量物的实际质量是______g.

题型:不定项选择

某同学通过下列实验测定粗盐中氯化钠的质量分数(杂质不溶于水).试根据实验步骤填空:

(1)调节托盘天平的零点,若天平指针偏向左侧,应将左侧的平衡螺母向______侧旋动(填左、右),使天平平衡.

(2)称取粗盐样品m1克.称量时在两个托盘上各放一张质量相同的纸,然后在______盘上放粗盐.

(3)溶解.将称好的粗盐倒入______中,加适量蒸馏水,用玻璃棒搅拌.

(4)过滤.过滤时,使滤液沿着玻璃棒流进过滤器,玻璃棒的末端要斜靠在______一边.

(5)蒸发滤液.加热蒸发滤液应在______里进行(填仪器名称).

(6)计算粗盐的纯度.称量所得纯净的氯化钠晶体,其质量为m2克,则粗盐的纯度为______.

题型:不定项选择

干姜配伍附子,可降低附子的毒性,属于()。

A.相须

B.相使

C.相畏

D.相杀

E.相反

题型:不定项选择

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