We carefully compared the result of the first experiment with_______ of the second one.
A:it
B:that
C:the ones
D:this
下图是广西某制糖厂生产流程图,据此回答下题。该生产模式的好处是( )
半径为R的光滑圆环轨道竖直放置,一质量为m的小球恰能在此圆轨道内做圆周运动,则小球在轨道最低点处对轨道的压力大小为( )