AL physics gravitation

total mechanical energy decrease係正確
k.e decrease先都正確,但係k.e decrease,p.e都係接下來decrease。你唔可以單考慮k.e。
PE = –GMm/r
Ek : Ep = 1 : –2
Total energy E = Ek + Ep =–GMm/2r
pe decrease係兩倍,因此Total energy下跌。-GMm/2r下跌。GMm/2r上升,因此r應該係細左。