valya ponkrat asked 2/8/2008 What Is The Main Purpose Of The Counter Weight Of A Railroad-crossing Barricade?
valya ponkrat asked 2/8/2008 You Set Up A Pulley To Help You Lift Something. You Anchor The Rope At One End And Arrange A Movable Pulley To Achieve A Mechanical Advantage Of 2. By The Time You Have Lifted The Object 5m Off The Ground, How Much Rope Have You Pulled Through The Pulley?
