《那些古怪又讓人憂心的問題》第88期:軌道速度(4)

5 This exponential increase is the centralproblem of rocketry: The fuel required to increase your speed by 1 km/smultiplies your weight by about 1.4. To get into orbit, you need to increaseyour speed to 8 km/s, which means you'll need a lot of fuel: 1.4 ×1.4 ×1.4 ×1.4 ×1.4 ×1.4 ×1.4 ×1.4 ≈15 times the originalweight of your g a rocket to slow down carries the same problem: Every1 km/s decrease in speed multiplies your starting mass by that same factor of1.4. If you want to slow all the way down to zero - and drop gently

5．指數式增長是火箭科學中的核心問題：速度每秒提升1千米，就需要自身質量×1.4千克的燃料。進入軌道要加速到每秒8千米，這需要1.48≈15倍自身重量的燃料。用火箭減速也會面臨相同的問題，速度每減少每秒1千米，就需要1.4倍自身質量的燃料。如果想要減速到零，並輕柔地再入大氣層，那麼還需要額外的15倍自身質量的燃料。

6 There are some good apps and online toolsto help you spot the station, along with other neat satellites.

6．網上有許多軟件可以幫你找到國際空間站和其他一些衛星的位置。

7 Either kind.

7．足球或橄欖球都行。

8 This type of play is legal in Australianrules football.

8．這麼玩在澳大利亞是被允許的。

9 Using song beats to help measure the passage of timeis a technique also used in CPR training, where the song “Stayin' Alive”is used.

9． 心肺復甦也會用歌曲的節拍計算時間，使用的歌曲是Stayin' Alive（活下去）。