It happens. Someone sends you a video but you can’t tell if it is real or fake. But what can you do? Physics. That’s what you can do. Typically, these videos show something flying through the air. Here are some things to look for that would show that it is fake:
- Real projectile motion has an object with a constant horizontal velocity and a constant acceleration in the vertical direction. If neither of these things are true, it could be fake.
- Time in the air. If it is plain projectile motion, you can calculate how long it should be in the air compared to how long it is actually in the air.
- Some videos are clearly possible, but maybe unlikely. How do you determine how unlikely something would be? You might have to model it (maybe with python) and see how often it works with some probability distribution of starting values.
- If the video doesn’t involve some type of projectile motion, you can still try to see if it agrees with some other fundamental physics concept.
Oh, and how do you get data from these videos? There are two common tools. Vernier’s Logger Pro software and Tracker Video analysis. Both can do the job. I prefer Tracker since it is free and has quite a few more features.
