Measuring Velocity with a Camera

I used my DSLR recording video at 60 fps to measure the velocity of NERF Darts. I was hoping this test would show that I could use my camera to measure velocities. Though I have faith in the velocities found the time it takes to find those is not conducive to multiple tests which I would feel necessary for potential future experiments I have planned.
Spreadsheet: docs.google.com/spreadsheets/...
I actually recorded this about six months ago (in June) but due to the amount of work to find the velocities and then not really knowing what to make of it I prioritized other videos.