初中物理力和机械选择题

下图中，属于省力杠杆的是 （   ）

如图所示是生活中常用的工具，其中属于省力杠杆的是（     ）

工厂为了搬运一个笨重的机器进入车间，某工人设计了下图所示的四种方案（机器下方的小圆表示并排放置的圆型钢管的根截面），其中最省力的方案是(    )

如图是研究杠杆平衡条件的实验装置，要想使杠杆平衡，A处钩码应挂（  ）

A．1个

B．2个

C．3个

D．6个

下列所示工具中，使用时不能省力但能省距离的是（   ）

如图所示的简单机械，忽略各种摩擦及杠杆和滑轮的重力，当提起相同重物时，最省力的是（   ）

如图所示的剪刀中，要剪开较硬的物体，使用哪种最合适（   ）

小明同学利用圆珠笔杆、钢丝、细绳制成了如图所示的滑轮组用其匀速提升重物下列说法正确的是

A．拉细绳的力F等于钩码重力G的1/3

B．拉细绳的力F等于钩码重力G的1/7

C．用该滑轮组提起不同的钩码，机械效率相同

D．用该滑轮组提起不同的钩码，机械效率不同

斜面是一种简单机械，生活中经常用到它，工人师傅小波和小新分别用如图所示的甲、乙两种方法，将同样的物体搬上车，下列说法正确的是

A．甲方法不可以省力，但能省功

B．甲方法可以省力，也能省功

C．乙方法可以省力，但不能省功

D．乙方法可以省力，也能省功

如图所示，我们在拖动行李箱时一般先拉出行李箱上方的拉杆，这样做的目的是为了

A．减小阻力臂，省力	B．增大阻力臂，省力
C．减小动力臂，省力	D．增大动力臂，省力

下列测量工具没有利用杠杆原理的是（　　）

下列工具在正常使用的过程中，可以看作费力杠杆的是

如图所示，杠杆处于平衡状态，则F的力臂是
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

A．OA

B．OC

C．OD

D．FD

如图所示，起瓶器开启瓶盖时，可看作是

A．以B为支点的费力杠杆	B．以B为支点的省力杠杆
C．以A为支点的费力杠杆	D．以A为支点的省力杠杆

“给我一个支点和一根足够长的棍，我就能撬起整个地球．”下列生产和生活中的杠杆与阿基米德设想的杠杆属于同一类型的是