问题
选择题
如图所示,物体A重100N,B重20N,当B匀速下降40cm时, A受到桌面的摩擦力和A移动的距离分别是

A.20N,40cm
B.10N,20cm
C.10N,80cm
D.20N,20cm
答案
答案:C
如图所示,物体A重100N,B重20N,当B匀速下降40cm时, A受到桌面的摩擦力和A移动的距离分别是
A.20N,40cm
B.10N,20cm
C.10N,80cm
D.20N,20cm
答案:C