题目

如图是一种拉杆式旅行箱的示意图，使用时相当于一个__________（填“省力”或“费力”）杠杆，若箱和物品共重100N，设此时动力臂是阻力臂的5倍，则抬起拉杆的力F 为__________N。 答案：省力  、  20--- Would you like to say something about the car show yesterday?--- Sorry.NickI went to see it.A. Either, or B. Neither, norC. Not only, but also D. Both, and