在“探究恒力做功与动能改变的关系”实验中,某实验小组采用如图甲所示的装置。实验步

题型:实验题

问题:

在“探究恒力做功与动能改变的关系”实验中,某实验小组采用如图甲所示的装置。实验步骤如下:

(1)把纸带的一端固定在小车的后面,另一端穿过打点计时器;

(2)改变木板的倾角,以重力的一个分力平衡小车及纸带受到的摩擦力;

(3)用细线将木板上的小车通过一个定滑轮与悬吊的砂桶相连;

(4)接通电源,放开小车,让小车拖着纸带运动,打点计时器就在纸带上打下一系列的点;

(5)测出s,s1,s2(如图乙所示),查得打点周期为T。

判断重力的一个分力是否已与小车及纸带受到的摩擦力平衡的直接证据是____。本实验还需直接测量的物理量是____(并用相应的符号表示)。探究结果的表达式是____(用相应的符号表示)。

考点:实验:探究功与速度变化的关系
题型:实验题

借贷记账法的特点有()。

A."借"表示增加,"贷"表示减少

B.以"借"、"贷"为记账符号

C.可根据借贷平衡原理进行试算平衡

D.以"有借必有贷,借贷必相等"作为记账规则

题型:实验题

81.有一个专题旅游团欲沿着长江考察,请回答下列问题:

(6)产于沿途省区的著名红茶、绿茶分别有哪些?(1分)

题型:实验题

对在线粒子监测装置有哪些要求?(FL-1-10)

题型:实验题

Few scientific fields are as full of risk as that of research into human intelligence. The two questions that (1) over and over again are "is it a result of nature or nurture" and "does race make a difference"

Making (2) comments about the second question can be a (3) move, as James Watson, a co-discoverer of DNA structure, recently found. He suggested that he was " (4) about the prospect of Africa" (5) "all our social policies are based on the fact that their intelligence is the same as ours (white people) (6) all the testing says not really". Such (7) by Dr. Watson are not merely (8) , they are scientifically weird. If the term (9) has any useful scientific meaning, then Africa, the continent where modern humanity began, is most racially diverse. The resulting (10) among the public forced Dr. Watson to leave his laboratory.

(11) , the study of the first question (12) between intelligence and genetics— has some wiser practitioners. One of them, Terrie Moffitt, of King’s College, has just (13) a project judging the relative importance of nature and nurture. Dr. Moffitt’s team (14) the effect on intelligence of breastfeeding, but in a genetic context. Previous studies have shown that breastfed children are more intelligent, (15) about six IQ points, than those given baby formulas.

The team, however, (16) the involvement of a gene called FADS2, which comes in two varieties, known as C and G. The researchers (17) if these two varieties interacted differently with breast milk. (18) on data from two groups of people, they found that the intelligence increase associated with breastfeeding only happened to people having (19) at least one copy of the C variety. The effect did not. (20) on the social classes or IQs of the parents.

8()

A.offensive

B.confusing

C.promising

D.objective

题型:实验题

患者王某,男性,30岁,因车祸致严重脑挫伤已昏迷1周,护士根据医嘱给予鼻饲,以补充营养和水分。

为患者进行鼻饲时,要求每次鼻饲量不应超过

A.100ml
B.150ml
C.200ml
D.250ml
E.300ml

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