如图所示容器中装有两种互不相溶且界限分明的液体,密度分别为ρ1、ρ2将一圆柱体放

题型:问答题

问题:

如图所示容器中装有两种互不相溶且界限分明的液体,密度分别为ρ1、ρ2将一圆柱体放入容器中,圆柱体的密度为ρ3.静止时圆柱体的上表面到分界线的距离为l1,如图1所示.将第一个圆柱体取出,再将另一形状与体积完全相同,但用不同材料制成的圆柱体放入容器中,静止时圆柱体的上表面到分界线的距离为l2,如图2所示,求后一圆柱体密度.

考点:密度的计算
题型:问答题

扩血管活性药是()

A.硝酸甘油

B.阿拉明

C.多巴酚丁胺

D.酚妥拉明

E.新福林

题型:问答题

How did the Olympic Games start In ancient Greece athletic festivals were very important and had p ________ (1). Originally the Festival was held in honour of .Zeus, the supreme god in Greek Mythology. Eventually the Olympian athletic festival had lost its ________ (2) and became an international event. No one knows exactly ________ (3) the Olympic Games go, but some scholars recorded date from 776 B.C.According to some scholars, at first the only Olympic event was ________ (4), called a stadium and that was the only event until 724 B.C. After that, other ________ (5) were added and sixteen years later in ________ (6) the pentathlon was added and wrestling became part of the games. This pentathlon was a five-event match which ________ (7) running, wrestling, leaping, throwing the discus, and hurling the javelin.The games were held ________ (8) and after an uninterrupted history of 1170 years, the games ________ (9) in A.D. 394, the Christian era, because of their pagan origin.It was over ________ (10) before there was another such international athletics gathering. In 1896, the first of the modern ________ (11) opened in Athens, Greece.Nowadays, the Games are held in different countries ________ (12). The host country provides vast facilities such as stadiums and ________ (13).Many more sports are represented, including the very celebrated event: ________ (14).The Olympics start with the arrival in the stadium of a torch, ________ (15) on Mount Olympus by the sun’s rays. The torch is carried by ________ (16) to the stadium. The Olympic flame symbolizes the ________ (17) of the ancient Greek athletic ideals, and it burns throughout the Games until ________ (18). The well-known Olympic flag, however, is ________ (19): the five interlocking rings symbolize the uniting of all five continents ________ (20).

题型:问答题

在探究摩擦力大小跟哪些因素有关时,小明选了两块相同的1kg长方体铁块做了如图10的系列实验.以下是部分实验步骤.(g取10N/kg)

第1次:把铁块平放在木板上,用弹簧测力计水平拉动铁块,使铁块做匀速直线运动(甲),读出弹簧测力计的示数,并记入下表中;

第2次:把铁块侧放在木板上,用同样的方法拉铁块(乙),记下相应的示数;

第3次:把两块相同铁块叠在一起平放在长木板上,再用同样的方法拉铁块(丙),记下相应的示数.

实验次数铁块对木板的压力/N弹簧测力计的示数/N摩擦力/N
1 5 
2 5 
3 10 
(1)将表格内的数据填写完整;

(2)三次实验完成后,比较第______两次的实验数据,可以发现:压力越大,所受的摩擦力也越大;

(3)比较第1、第2两次实验数据,可以初步得出的结论是:______.

题型:问答题

锅炉加药的作用是()

A.除掉水中的钙镁离子

B.在设备内部形成稳定的钝化膜

C.保证蒸汽质量

D.不形成水垢

题型:问答题

船舶、排筏在能见度不良时锚泊应发出何种声响信号?

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