Answer:
constant, increase, decrease, constant
Explanation:
Not 100% sure but thought I could be of some help. If the arrows are the same size and length it remains constant. If it is longer to the right then it increases (means more force pulling it forward). However if it is longer in the other direction, this is likely to be friction which will slow it down. This is depending on which direction the box is meant to be moved in which is to the right in this case.
