题干

对于用天平、量筒测某种液体的密度来说,其实验设计有如下二种方案:

方案一:
A.将烧杯中的适量液体倒入量筒中,读出液体的体积V
B.用天平测出空烧杯的质量m1
C.再将量筒中的液体倒入烧杯,放在天平上测出总质量m2
D.用公式算出液体的密度ρ液
方案二:
A.在烧杯中盛被测液体,测出它们的质量m1
B.将烧杯中的适量液体倒入量筒中,读出液体的体积V
C.测出烧杯和杯中剩余液体的质量m2
D.用公式算出液体的密度ρ液

(1)一、二两种方案,选第____ 种方案进行实验,实验误差最小。
(2)用你选择的方案进行实验,所测密度的表达式ρ液体=____ 。
(3)经过思考小明将另一方案稍加改进,提高了测量结果的准确性。改进后的步骤C分为两步,请你帮他写出改进内容:
第一步:____ 
第二步:____ 
(4)用步骤中的字母,写出方案改进后小明所测液体密度的表达式ρ'液体=____ 

上一题 下一题 0.0难度 选择题 更新时间:2019-10-02 10:08:57

答案(点此获取答案解析)

\u4e8c,\u03c1\u6db2\u4f53\uff1d(m1-m2)/v,\u5c06\u91cf\u7b52\u4e2d\u90e8\u5206\u6db2\u4f53\u5012\u5165\u70e7\u676f\uff0c,\u6d4b\u51fa\u603b\u8d28\u91cfm2;\u518d\u8bfb\u51fa\u91cf\u7b52\u4e2d\u5269\u4

同类题3

选择正确的句子序号,补全文章。

Building Trust in a Relationship Again

          Trust is a learned behavior that we gain from past experiences.____(1)Trust is a risk.But you can't be successful when there's a lack of trust in a relationship that results from an action where the wrongdoer takes no responsibility to fix the mistake.21·cn·jy·com

          Unfortunately,we've all been victims of betrayal.Whether we've been stolen from,lied to,misled,or cheated on,there are different levels of losing trust.Sometimes people simply can't trust anymore.____ (2)It's understandable,but if you're willing to build trust in a relationship again,we have some steps you can take to get you there.

          ●____(3)Having confidence in yourself will help you make better choices because you can see what the best outcome would be for your well-being.

          ●____(4)If you've been betrayed,you are the victim of your circumstance.But there's a difference between being a victim and living with a “victim mentality”.At some point in all of our lives,we'll have our trust tested or violated.

          ●You didn't lose “everything”.Once trust is lost,what is left?Instead of looking at the situation from this hopeless angle,look at everything you still have and be thankful for all of the good in your life.____(5) Instead,it's a healthy way to work through the experience to allow room for positive growth and forgiveness.

A.Learn to really trust yourself.

B.It is putting confidence in someone.

C.Stop regarding yourself as the victim.

D.Remember that you can expect the best in return.

E.They've been too badly hurt and they can't bear to let it happen again.

F.This knowledge carries over in their attitude toward their future relationships.

G.Seeing the positive side of things doesn't mean you're ignoring what happened.