A:当推力为75N 时,箱子不动,此时推力等于地面对箱子的摩擦力
B:当推力增大时,箱子由静止开始运动,说明力可以改变物体的运动状态
C:当推力为100N 时,箱子做匀速直线运动,地面对箱子的摩擦力为100N
D:当推力为200N 时,箱子做加速直线运动,地面对箱子的摩擦力为200N
下列过程中,没有发生膜融合的是 ( )
在同一坐标系下,下列曲线中,右焦点与抛物线y2=4x的焦点重合的是( )
化简:c2-a2-a-c=____
根据对话内容从方框中选择能填入空白处的最佳选项补全对话,其中有两项多余。
A:____
B:A map o four city.
A:What place are you looking for?
B:The new train station.
A:Here it is.____
B:Yes.
B:No.I'm going to meet Mr Tang there.
B:My English teacher online.
B:You're right.
A.How much is your map?
B.It's near Gao Qi's home.
C.Who is he?
D.What's this?
E.Well,you often talk with him
F.Where is he from?
G.Are you going to take a train?