Rotational Physics

Factual Questions
1

So I understand how the first experiment in my physics class works:

Sitting on a rotating stool, you spin a bicycle wheel vertically, holding handles on either side of the wheel. You then turn the wheel horizontal, and depending on which way you turn it, you will start to turn on the stool. That can be explained as easy as, the outside of the wheel has a greater angular velocity, so to compensate, you spin in the opposite direction of the outside of the wheel.

THE QUESTION: What’s up with this? /
What still boggles me is the next experiment:

Holding onto one side of the wheel, spin it. Grab the string (length ≥ radius of wheel) which is attached to the end of the handle of the wheel. Let go of the handle, holding only onto the string. With enough spin, or angular velocity, the bicycle wheel will stay vertical and parallel to the string (for a time, before friction starts to slow it down). And I can feel the entire weight in the handle, obviously, but it’s just so counter-intuitive!

This isn’t really a frontpage/Cecil question, just something I’d like explained better than the textbook can supply. I can handle all the math, it’s just conceptualizing the way the weight is sent to the end of the handle, I guess.

Thanks for any help!

2

The short story is that (a) every object has a resistance to motion (called inertia) and a round body has a resistance to spinning (often called the inertia of the wheel). Now, (b) as you know, energy is never lost nor created, but guess what? His cousin is named “momentum” who is never lost nor created as well. And, his twin is called “angular momentum” (fyi: angular = rotational) who doesn’t get lost nor created, neither. As such, changing the plane in which the wheel starts spinning has changed the angular (rotational) velocity (not necessarily the rotational speed, understand?) of the wheel. Thus, to conserve angular momentum, you sense the result which moves your swivel chair accordingly.

Basically, the same is true for the second part of your question. Spinning objects resists changes in the plane in which they spin much like how a body at rest doesn’t likes to move…kinda like people at rest! That’s the short of it!