Ahsoka Physics: Video Analysis of a Space Jump
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You know I’m watching Ahsoka, right? At the same time, I’m always keeping an eye open to find a new Star Wars Physics post (here’s my giant list so far). OK, so how about that scene in Part 3: Time to Fly? Wait! Here’s your spoiler alert. But I guess the above sketch gives you a clue about the particular episode.
If you are still here, then let’s get into the physics. If you don’t recall the scene, Ahsoka and Sabine’s star ship is temporarily disabled while fighters are attacking. In order to stall for time, Ahoska goes out on the wing (in a space suit) and engages the enemy with her light saber (it’s a very Clone Wars type of move — I love it). At one point, she leaps off the ship to avoid a fighter and then lands back on a different part of the ship. Here’s the move.
Well, what are we waiting for? It’s time for some video analysis. Of course I’m going to use Tracker Video Analysis (it’s free) to get the position-time data from this motion. There are a few things I need to think about before starting.
- The camera angle changes during the motion, so I will need to adjust for that (which is pretty easy with Tracker using the calibration point pairs — here’s an example).
- What is the distance scale in this video? I’m going to use a rough approximation based on Ahsoka’s height of 1.7 meters (which is actually the height of Rosario Dawson — who plays Ahsoka).
- Finally, I’m going to assume the clip plays in “real times” so that at 30 frames per second each frame is actually 1/30th of a second.
In the space-craft frame (not the camera frame), I get the following data for the horizontal position as a function of time.
A linear fit gives a constant x-velocity of 4.12 meters per second. Notice the jump in the data — that’s from the quick cut to a camera showing the motion from above, it then switches back to the normal view. Since the velocity in the horizontal direction…
