Was doing this question, but became confused on what it is... (kinda know what b and c are - but a I am not too sure about)
View attachment 34948
First, measure the distance between the original position to the final position horizontally.
The scale is 1 mm to 1 cm (the distance between white line given is 15 cm apart which is 15 mm when you measure it).
The horizontal distance you get should be 0.34.
There is 30 flashes per second but only 5 flashes in the image (the first one doesn't count since it was the start).
to the right of the page.
you could round it to 2 ms^-1.