Modeling the Motion of a Tossed Ball in an Accelerating Elevator

Rhett Allain
8 min readMar 4, 2021
Photo: Rhett Allain. Two views of a ball tossed in an accelerating elevator.

There is this great elevator in the Hyatt Regency hotel in New Orleans. First, it’s a fairly high acceleration elevator (some of them are just super weak). Second, it’s got a nice glass window on the side. This means you can see outside as you move up floor. But it also means that people can see outside INTO the elevator.

So, here is the fun physics question:

“What happens when you toss a ball up inside an accelerating elevator?”

I actually have a video of this situation. Check it out.

If you like, you can use video analysis to find the acceleration of the elevator and of the ball — but I will let you do that as a homework exercise.

Instead, I’m going to model this motion (with python) from two different reference frames. First, I will look at the motion of both the elevator and the ball from a stationary viewpoint outside of the elevator (this would be an inertial reference frame). Second, I will model the motion from the non-inertial reference frame inside the elevator.

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Rhett Allain

Physics faculty, science blogger of all things geek. Technical Consultant for CBS MacGyver and MythBusters. WIRED blogger.