5cm/s=( )km/h;20dm=( )km/h

问题描述:

5cm/s=( )km/h;20dm=( )km/h

5cm/s=5*3600cm/3600s=18000cm/3600s=0.18km/h
20dm/s=20*3600dm/3600s=72000dm/3600s=7.2km/h