M = W/F = 2Da/Da-Db
900/150 = 2Da/Da-Db
6Da - 6Db = 2Da
=>Da/Db = 3/2
19.有一惠斯登差動滑車,欲以 150N 之施力吊起 900N 之重物,若不計摩..-阿摩線上測驗