某实验小组采用如图1所示的装置探究功与速度的关系,小车在橡皮筋的作用下弹出后,沿

题型:填空题

问题:

某实验小组采用如图1所示的装置探究功与速度的关系,小车在橡皮筋的作用下弹出后,沿木板滑行.打点计时器工作频率为50Hz.

(1)实验中木板略微倾斜,这样做______.

A.是为了使释放小车后,小车能匀加速下滑

B.是为了增大小车下滑的加速度

C.可使得橡皮筋做的功等于合外力对小车做的功

D.可使得橡皮筋松弛后小车做匀速运动

(2)实验中先后用同样的橡皮筋1条、2条、3条…,并起来挂在小车的前端进行多次实验,每次都要把小车拉到同一位置再释放小车.把第1次只挂1条橡皮筋对小车做的功记为W,第2次挂2条橡皮筋时橡皮筋对小车做的功为2W,…;橡皮筋对小车做功后而获得的速度可由打点计时器打出的纸带测出.根据第4次实验的纸带(如图2所示)求得小车获得的速度为______m/s.

(3)若根据多次测量数据画出的W-v图象如图3所示,根据图线形状可知,对W与v的关系作出猜想肯定不正确的是______.

A.W∝

v
B.W∝
1
v
C.W∝v2D.W∝v3

(4)如果W∝v2的猜想是正确的,则画出的W-v2图象应是______.

考点:实验:探究功与速度变化的关系
题型:填空题

For nearly ten years, the Unified Modeling Language (UML) has been the industry standard for visualizing, specifying, constructing, and documenting the ()of a software-intensive system. As the()standard modeling language, the UML facilitates communication and reduces confusion among project(). The recent standardization of UML 2.0 has further extended the language’s scope and viability. Its inherent expressiveness allows users to()everything from enterprise information systems and distributed Web-based applications to real-time embedded systems.

The UML is not limited to modeling software. In fact, it is expressive enough to model()systems, such as workflow in the legal system, the structure and behavior of a patient healthcare system, software engineering in aircraft combat systems, and the design of hardware.

To understand the UML, you need to form a conceptual model of the language, and this requires learning three major elements: the UML’s basic building blocks, the rules that dictate how those building blocks may be put together, and some common mechanisms that apply throughout the UML.

the UML facilitates communication and reduces confusion among project()

A.investors

B.developers

C.designers

D.stakeholders

题型:填空题

从高分子(polymer)的重复结构单元(mer)的对称性可知,最易结晶(crystallization)的是______。

A.聚丙烯(polypropylene)

B.聚乙烯(polyethylene)

C.聚苯乙烯(polystyrene)

题型:填空题

It is recommended that you ________ your accommodation in advance in tourist season, as you may find all the best hotels are not accessible.

A.book

B.must book

C.will book

D.shall book

题型:填空题

下列哪个选项不能作为客户不满意调查的信息获取渠道:()。

A.现有客户

B.潜在客户

C.已失去客户

D.竞争者客户

题型:填空题

通常认为正常的速动比率为( ),低于这一数字被认为是短期偿债能力偏低。

A.0.5

B.1

C.2

D.3

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