(b) speed of ball changes every 10 seconds.
(c) average speed of ball over any 20 second interval is fixed.
(d) the acceleration of ball is the same as from the train.
Differences between cellpadding and cellspacing are as follows:
Cellpadding
Cellspacing
Cellpadding is used for formatting purpose which specifies the space needed between the edges of the cells and also in the cell contents.
Cellspacing...