Reading from left to right, describe the spacing between the dots in lines 1, 2, and 3.

Answers

Line 1: The spacing is the same. Uniform

Line 2: The spacing is increasing.

Line 3: The spacing is decreasing.

Explanations

The dots seems to be the one made by a ticker tape timer. A device that used to find the velocity/acceleration of bodies at a short distances.

Line 1

When you look at the space between the dots in line 1, you will see that the gaps are uniform. The distances between the dots are  the same. If the dots were from a ticker time, then it would represent a constant velocity.

Line 2

The spaces from the left are be coming bigger as you move to the right. That is the spacing is increasing. If it is from a ticker time, these would represent an  increasing velocity.

Line 3

The spaces are decreasing from left to right. That is the distance is becoming smaller. For a ticker timer is could mean a decreasing the velocity.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.