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Real World Physics: Estimating the Acceleration of a Train
Sometimes you see stuff in the real world that would just make a fun physics problem. It’s not a textbook problem with a bunch of given values that you just plug into an equation — no, it’s going to be fun.
Here’s a quick clip that I posted online after seeing a train accelerate away from the station.
OK, I’ll admit this is not a perfect video for a physics analysis. First, the camera is oriented vertically so that you can see as much of the motion in the horizontal direction. Second, there’s not a perfect object to scale the video. Also, I probably should have recorded for a longer period of time — but I started to feel awkward standing still in the crosswalk.
Acceleration Using Time and Car Length
Of course we can get time from the video frames — but what about distance? How about looking at the times it takes for a car length to pass one of those trees? If the train is indeed accelerating, then the time it takes for later cars should be LESS than the time for earlier cars…
