挑战习题
1/5单选题
难度:

1.

用如图所示的滑轮组匀速提升一个重为G的物体,不计摩擦和滑轮的重力,则拉力F的大小是(  )



A

B

C

D

G

提示1:
PHA+5Yqo5ruR6L2u55yB5Yqb77yM5ouJ5Yqb5bCP5LqORzwvcD4=
提示2:
PHA+5Lik6IKh57uz5a2Q5ouJ5LiL6Z2i54mp5L2TPC9wPg==
提示3:
PHA+5ouJ5YqbRuetieS6jjEvMkc8L3A+
正确答案:Qg==
PGRpdj7liqjmu5Hova7nnIHlipvvvIzmnInkuKTogqHnu7PlrZDmi4nkuIvpnaLniankvZPvvIzmr4/ogqHnu7PlrZDmi4nlipvkuLpG77yMMkY9R++8jEY9MS8yR+OAgjwvZGl2Pg==