由动能定理
-mgh-μmghcosa/sina=0-0.5mv0^2
h=v0^2/2g(1+μcosa/sina)
由动能定理
-2μmghcosa/sina=0.5mv^2-0.5mv0^2
v=v0[(1-2μcosa/sina(1+μcosa/sina)]^1/2