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问题 选择题

下列数据是对同一物体的长度进行的四次测量的结果，其中错误的是（　　）

A．9.87cm

B．98.6mm

C．0.985m

D．0.986dm

答案

98.6mm=9.86cm，0.985m=98.5cm，0.986dm=9.86cm．

可以发现选项C--0.985m与其它三个数值明显差别，所以此数值是错误的．

故选C．

实验题

在“探究加速度与力、质量的关系”的实验中，采用右图所示的装置．

小题1:下列说法中正确的是   ▲  ．

A．木板一端垫高，是为了小车有更大的加速度，方便测量

B．砝码盘和砝码的总重力就是小车受到的合外力

C．探究加速度a与质量m的关系时，为了直观判断二者间的关系，可作出a－m图象

D．当小车的质量远大于砝码盘和砝码的总质量时，才能近似认为细线对小车的拉力大小等于砝码盘和砝码的总重力大小小题2:实验中得到以下两个实验图线甲、乙，描述加速度与质量关系的图线是  ▲   ；描述加速度与力的关系图线是  ▲  ；图线 ▲  也可以描述加速度与质量的倒数关系．

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单项选择题

Salesperson: The picture tube is the central component of any television, and Picturesque televisions use the same highquality picture tubes as those used in TruVue televisions.
Since you pay a much lower price for a Picturesque, you pay a lower price for a television with the same picture quality when you buy a Picturesque instead of a TruVue.
Which of the following is an assumption that, if justified, would allow the conclusion of the salesperson’s argument to be properly drawn

A．TruVue televisions are much more widely advertised than are Picturesque televisions.

B．The picture quality of a television is determined solely by the quality of its picture tube.

C．A salesperson earns much less on the sale of each Picturesque television than on the sale of each TruVue television.

D．Many more Picturesque televisions are sold each year than TruVue televisions.

E．(E) Picturesque televisions are assembled in the same factory that assembles TruVue televisions.
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