We took SteelyKid to the playground at one of the local elementary schools on Sunday morning. this one includes an odd sort of slide, made of dozens of rollers that are 1-2 inches in diameter (they’re all the same size– the range is just because I didn’t measure them carefully). They’re on really good bearings, and while it’s kind of noisy, it’s a reasonably smooth ride.
There is, however, one slightly mysterious aspect to this slide, clearly visible in this video that Kate was good enough to shoot for me:
SteelyKid takes something like 6 seconds to go down the slide, while it only takes me about 2 seconds to reach the bottom. This is kind of surprising, as it’s the reverse of most of the other slides we go on– usually, she handily beats me to the bottom on any set of parallel slides.
It’s also not what you would expect for an idealized slide from introductory Newtonian physics. The acceleration of an object sliding down a ramp, even with friction, should not depend on the mass of the object. And yet, I very clearly go faster than SteelyKid does, and while I don’t have the video to test it qualitatively, I’m pretty sure Kate’s rate of sliding falls between SteelyKid and me.
So, the question for you is: Why does that happen?
After a bunch of playing around with Tracker Video (I probably owe Rhett a dollar for blog infringement), I have a possible theory, but I’m really not 100% sure what’s going on here. So I’ll throw this out to my readership: Why do I go down the roller slide so much faster than SteelyKid does, when that’s not what happens on a regular slide? Leave your theories in the comments, and I’ll post my analysis and my guess at the answer later in the week.
(Also, the “Go, Daddy, go!” from SteelyKid after she exits the frame is totally worth uploading this to YouTube in its own right…)