Andy carried out the experiment below. He rolled the iron ball down the wooden plank and recorded the time taken for the ball to travel from A to M and from M to V before and after object X was placed below the wooden plant as shown below. The results were then recorded in the table below.

Time taken to travel from A to M (s)Time taken to travel from M to V (s)
Without object X1526
With object X1134

Which of the following is/are possible explanation(s) for the difference in the time taken for the ball to travel from one point to another point?

(You may select more than one answer)