A.1.95cm,2.54cm,3.8cm B.19.05mm,25.4mm,38mm C.19.5mm,25.3mm,38mm D.1.9cm,2.53cm,3.8cm
因?yàn)閚1/n2=Z2/Z1 所以n2=n1*Z1/Z2=1450×2/62=46.78r/min.