Abat hits a ball; which has the greater acceleration, the bat or the ball?

The ball.

Explanation: Right before the impact, the bat will have a bigger acceleration than the ball (assuming that the ball is trowed softly), and after the impact, there will be some energy of the bat transferred to the ball. As the ball has a lot less mass than the bat, it is "easily" accelerated:

Remember that the second Newton's law says that:

F = m*a

So, after the impact, the ball has a greater acceleration than the bat (Also, if the bat had more acceleration than the ball, it will "push" the ball, but you can see that the ball "escapes" to the bat after the initial impact).

b) phosphorus pentoxide

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.