如图所示，在“测量滑轮组机械效率”的实验中，物体重6N．沿竖直方向匀速拉动弹簧测力计，物体上升高度为10cm，此时弹簧测力计的示数为____N，滑轮组的机械效率是____．

阅读图文材料，完成下列要求。

    湖南境内矿产资源丰富，已探明的矿产有煤、铁、钨、铅、锌、金、锡、铀、钼、铜、银、铌、钽、稀土等40余种，为著名的有色金属之乡。湘江流域冶金、机械、化工、新材料等产业是支柱产业。冶金产业在迎来发展的同时，也产生了严重的环境问题。长沙是全国最重要的有色金属交易中心。下图为湖南省简图。

仔细阅读下面的信息,然后填写表中的内容
Dear Wang Hong,
I am an American school girl. My name is Alice Green. I am twelve. There are five people in my family-my brothers, my parents and I. My brothers and I are all students at the same school. We go to school from Monday to Friday. We don't have any classes on Sundays or Saturdays. My father and mother are teachers. They say, China is great, and  Chinese people are friendly, I want to travel in China. I think it is very interesting, isn't it? I like reading. Now I am reading a book of Chinese stories. They are very interesting. My brothers and I like playing soccer and basketball. What do you like?
Let's be friends. Please write soon.
Yours,
Alice Green
Information Card

清明假期，小明全家驾车从南京到国际慢城游玩，出发前，爱学习的小明收集了相关数据，整理成如表，请你根据表中数据完成相关计算．

（1）轿车静止时对水平地面的压强（g取10N/kg）；

（2）匀速行驶lkm牵引力做功多少？

（3）全程消耗的汽油在完全燃烧时放出的热量（q_汽油=4.6×10⁷ J/kg）．