(9分)在“测酸奶密度”的实验中, (1)小明的实验方案:用天平和量筒测密度。

题型:实验题

问题:

(9分)在“测酸奶密度”的实验中,

(1)小明的实验方案:用天平和量筒测密度。

①(2分)把天平放在水平桌面上,将游码移到零刻度处,发现指针静止时指在分度盘中央刻度线的右侧,要使天平平衡,他应该(     )

A.把横梁右端螺母向右旋出一些

B.把横梁右端螺母向左旋进一些

C.把天平右盘的砝码减少一些

D.向右移动游码②(各1分)他用已调节好的天平测得空烧杯的质量m0为37.4 g;接着把酸奶倒人烧杯中,测得烧杯和酸奶的总质量m1,如图甲所示m1=________g;然后把烧杯中的酸奶倒人量筒中,如图乙所示,V=________cm3;则酸奶的密度ρ=_______________kg/m3

       

③(2分)在交流讨论中,小雨同学认为小明测得的酸奶密度值偏大。其原因是___________________________________________________________;

(2) (2分)小雨的实验方案:巧妙地利用天平、小玻璃瓶(有盖)和水测酸奶密度。

小雨的实验过程是:①用天平测出小玻璃瓶(含盖)的质量m0

②在瓶内装满水,盖上盖子,用天平测出瓶和水的总质量 m1  

③倒干净水,再往瓶内装满酸奶,盖上盖子,用天平测出瓶和酸奶的总质量m2

则酸奶密度的计算表达式(用测量的物理量符号表示) ρ=_____________________

考点:固体密度的测量
题型:实验题

婴幼儿最理想的钙来源是() |食物中蛋白质含量最高的是()

A.大豆

B.肉类

C.粮谷

D.乳及乳制品

E.蛋类

题型:实验题

When you first drift off into slumber, your eyes will roll about a bit, your temperature will drop slightly, your muscles will relax, and your breathing will become quite regular. Your brain waves slow down a bit, with the alpha rhythm predominating for the first few minutes. This is the first stage of sleep. For the next 30 minutes or so, you will drift down through Stage 2 and Stage 3. The lower your stage of sleep, the slower your brain waves will be. About 40-60 minutes after you lose consciousness, you will reach the last stage. Your brain waves will show the delta rhythm. You may think that you stay at this deep stage all the rest of the night, but that turns out not to be the case. About 80 minutes after you fall into slumber, your activity cycle will increase slightly. The delta rhythm will disappear, to be replaced by the activity pattern of brain waves. Your eyes will begin to dart around under your closed eyelids. This period of Rapid Eye Movements lasts for 8-15 minutes and is called REM sleep.
During both light and deep sleep, the muscles in your body are relaxed but capable of movement. As you slip into REM sleep, a very odd thing occurs -- most of the voluntary muscles in your body become paralyzed. Although your brain shows very rapid bursts of neural activity during REM sleep, your body is incapable of moving. REM sleep is accompanied by extensive muscular inhibition.

The lower your stage of sleep,______.

A.the faster your eyes will roll about

B.the quieter your breath will become

C.the slower your brain waves will be

D.the higher your temperature will be

题型:实验题

临床资料:男,45岁,常规体检。

超声综合描述:肝回声增强明显不均,可见多发片状低回声区(箭头所指)。

超声提示()

A.肝弥漫性结节性肝硬化

B.肝多发占位

C.非均匀性脂肪肝

D.血吸虫性肝硬化

题型:实验题

维生素B1保持稳定的条件是()。

A.酸性

B.碱性

C.中性

D.光照

E.铜离子存在

题型:实验题

法治思维主要表现为()

A.价值取向

B. * * 保障

C.正当程序

D.规则意识

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