ma1=GMm/r2ma2=GMm/R2a1/a2=R2/r2GMm/r2=mv12/rGMm/R2=mv22/Rv1/v2=√(R/r)生命太过短暂，今天放弃了明天不一定能得到。
ma1=GMm/r²ma2=GMm/R²a1/a2=R²/r²GMm/r²=mv1²/rGMm/R²=mv2²/Rv1/v2=√(R/r)
