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[what if]第70期:无尽割草机Comments>>

发表于 2013-11-08 20:39 | Tags 标签:, , ,

提问:

要有多大一个草坪才能让割草的速度赶不上草长的速度?

—— Nick Nelson

回答:

根据伊利诺伊香槟分校(UIUC)的Turfgrass Extension and Outreach项目[1]的规范,每次割草都需要割去草茎三分之一的高度。

wpid-06021324_97214-2013-11-6-15-39.gif

草长得快慢取决于天气的差别,但我们不妨假设草每天长0.2英寸(约5毫米)。这个数字来自于爱荷华州Yard and Garden Extension项目中发布的《Mowing Your Lawn》文件。(我个人觉得这个项目的参与人员故意与UIUC的成员在竞争)

普通的手推式除草剂在较快的步行速度下每秒能够给1平方米不到一点的草坪除草。如果你从早上八点连续干到晚上六点,你能完成2.5万平方米的除草面积。[2]为了把草皮的高度保持在4英寸,你每十天就需要除一次草。如果你除草的频率高一点或者低一点,那么你家的草坪就有可能要遭殃——更坏的情况是让UIUC的人士不高兴。

如果你每天除草10小时,那么在剪过的草的高度再度超标之前你可以完成0.25平方千米的除草工作。也就是说如果整个梵蒂冈城屋里屋外都被多年生黑麦草所覆盖,[3]你有能力保证半座城的草坪整整洁洁高度不超标。

wpid-06021651_42082-2013-11-6-15-39.gif

如果你有更大更快的除草机,你就能包管更大的区域。在每小时前进12英里[4]的速度下,一个加大版的轮式除草机可以完成最多2平方千米区域的除草工作。我在Wolfram|Alpha上查到这差不多是一头成年美洲豹活动区域面积的0.5%到1%。

wpid-lawn_cougar-2013-11-6-15-39.png

2010年Bobby Cleveland驾驶着轮式除草机以超过96英里的时速打破了世界纪录。Bobby这么干的原因之一在于英国除草机驾驶员Don Wales早些时候从他手中夺去了最快除草机的荣誉,Bobby这次又把世界第一赢了回来。[5]

不过现在这个世界第一又不在美国人手里了,因为在前几年《Top Gear》杂志委托本田公司为他们打造了一台更快的除草机。几个月前,这个屁股喷着火焰的除草机在法国的一条测试赛道上跑出了超过100英里的时速。[6]建造这台怪物的人声称它能跑到每小时130英里。虽然这台除草机还是能除草(用的是定制的机械装置),但为了安全起见,它在以最高速度运行时修剪器被拆了下来。

有了Top Gear的神级除草机,我们能打理的草坪最大能游多大?

假设我们先把安全性抛之脑后,把修剪器再装回去,再假设在以最高速度运行时一下能除2米宽的草。

又如果这台除草机24小时不停地除草……

wpid-lawn_cougar_2-2013-11-6-15-39.png

……那么它差不多刚好能把一头成年美洲豹的整个活动范围内的草打理完。

  • 注1:UIUC管理的Morrow Cornfields是世界上最值钱的玉米地,也是世界上历史最久的科学实验项目之一。
  • 注3:也许是某个脑残UIUC研究生的项目创想……
  • 注5:真的。
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14 Responses to “[what if]第70期:无尽割草机”

  1. Mewton说道:

    这期怎么没有序号了?

  2. wrb说道:

    69 70好没意思啊 等下周三71了

  3. 道明说道:

    昨天不是这个标题吧

  4. George说道:

    @猪的米 ,你赶上原文进度了,介意翻译一下一直没人译的第13期吗?

    • 猪的米说道:

      第13期已经有人翻译了哎 传送门http://blog.renren.com/share/100214002/14337977334

  5. 无脸门门主说道:

    开着这种除草机去参加F1一定狠拉风……

  6. 小虎子说道:

    僵尸克星除草机

  7. Illusiwind说道:

    注3, undergraduate是本科生啊,本科生!
    注5, 链接没有了……

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