I hope you will have a good journey.
A:have a wonderful party with your friends at home
B:have a good time with your friends
C:will travel happily from one place to another
用同样大小的力F,分别以图所示的方式依次作用在同一木箱上,使木箱向右运动,其中滑动摩擦力最小的是()
实验目的:
用高锰酸钾制取一瓶氧气,做细铁丝燃烧的实验.