[筆記] IFgo 神奇角動量

[askus (小三)]

問一下.. +_+

   _>   N  _>       _>           d            d
Σ li = Σ(Rcm(t) + Ri'(t))*mi*(---- Rcm(t)+  -- Ri(t))
        i=1                      dt           dt

    N           d                       d                  d
=> Σ{mi*Rcm(t)*--- Rcm(t) + mi*Rcm(t)*--Ri(t) +mi*Ri'(t)*--Rcm(t)
   i=1          dt                     dt                 dt
                    d             ↑            ↑
        +mi*Ri'(t)*--Ri(t)}       ↑            ↑
                   dt             ↑            ↑

為什麼 Ifgo 說 其中 中間兩項(指標處)為零呢?_?

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