A:on; have traveled
B:to; will have traveled
C:towards; have traveled
D:about; travel
如图所示,上下开口、内壁光滑的铜管P和塑料管Q竖直放置,小磁块先后在两管中从相同高度处由静止释放,并落至底部,则小磁块( )
如图所示,物体浸没在水中时,所受到的浮力为____N;从图乙、丙可以看出浮力的大小与液体的____有关。