A year has twelve months. My favorite month is October. October 1^st is National Day(国庆节）. We have a seven-day holiday(假期). During the holiday, my parents always take me to see my grandparents.

    Our school has some interesting things in October. On the 12th , we have a soccer game. I don't love basket ball. It's difficult for me. But I love soccer. I love playing soccer and watching soccer games. We have a book sale on October 20th. I have three old books and I want to sell them. The art festival is fun. We have it on October 29th. My birthday is also on this day. October is a really great month for me.

实验室有如下器材：天平（含砝码）、量筒、烧杯（2个）、弹簧测力计、金属块、细线（质量和体积不计）、足量的水（密度已知）、足量的未知液体（密度小于金属块的密度）

阅读下面的文言文，回答小题。

      【甲】水陆草木之花，可爱者甚蕃。晋陶渊明独爱菊。自李唐来，世人甚爱牡丹。予独爱莲之出淤泥而不染，濯清涟而不妖，中通外直，不蔓不枝，香远益清，亭亭净植，可远观而不可亵玩焉。

       予谓菊，花之隐逸者也；牡丹，花之富贵者也；莲，花之君子者也。噫！菊之爱，陶后鲜有闻。莲之爱，同予者何人？牡丹之爱，宜乎众矣！

      【乙】余忆年少时，住西湖。每至夏日，临湖赏荷，便欣然忘食。一日，偕数友，观荷于湖边亭中。兴正浓，忽有大雨倾盆而至，湖中荷花尽作飘摇之态。少时，雨过天晴波澜不惊湖天一色。荷花为雨所洗，鲜妍明媚，袅娜多姿，清丽雅致，实为花中仙子也。李太白诗云“清水出芙蓉，天然去雕饰”，余以为妙绝。

一实心物体，重为800N，体积为0.1m³，投入河水中静止（g取10N/kg）．求：