(1)由系统机械能守恒
2mgL-KmgL=0.5(2m+km)v²
v=[2(2-k)gL/(2+k)]½
(2)Q=0.5mv²=mg(2-k)gL/(2+k)
(3)mgL-KmgL=0-0.5(k+1）mv²
k^2=2 k=2½=1.414
(1)由系统机械能守恒
2mgL-KmgL=0.5(2m+km)v²
v=[2(2-k)gL/(2+k)]½
(2)Q=0.5mv²=mg(2-k)gL/(2+k)
(3)mgL-KmgL=0-0.5(k+1）mv²
k^2=2 k=2½=1.414