A.0.5~1.0倍 B.0.8~1.2倍 C.1~1.5倍 D.1.5~2倍
A.0.5倍 B.0.7倍 C.0.9倍 D.1.0倍
A.v=πDn/10(m/min) B.v=πDn/100(m/min) C.v=πDn/1000(m/min) D.v=πDn/10000(m/min)