I don't have a link to a tutorial, but I think you almost answered your own question. To make a 3D animation using a 2D physics engine like Newton, you need to think about the motion with only 2 axes.
So, to make something like the example you liked above, you would create a simulation in Newton looking along the X-axis from one side. The way I usually do this is to create 2D shape layers which correspond to the profile of the layer you want to animate in 3D - so, in your example, a slim rectangle - and parent the layers to be animated in 3D to those shape layers. You'll want to rotate the 3D layers around the Z-axis so that you are looking at them from the side.
If you search for Newton rope tutorials, you'll see how to link shapes together using different types of joint. Tweak the settings to get the effect you want and then export the keyframe data. The shape layers (which you can now hide) will animate realistically and the child layers will animate along with them. Hope that helps...
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