Moment of Inertia demo wheel

thingiverse

These wheels allow you to demonstrate the concept of the moment of inertia. The wheels have three rings of holes, at 25, 37.5, and 50mm distance from the center. You can put M8x30mm bolts through the holes and secure them with nuts on the other side to selectively add mass to the wheels. The most basic demo is to print two wheels, and put 8 bolts in the inner ring of one wheel, and 8 bolts in the outer ring of the other wheel. Then you roll both wheels down an inclined plane. You can use a plank and some books for instance. I don't have easy access to US standard fasteners, but my math says 5/16th bolts of 1.25inch length should work. I made a video on these you can find here: https://www.youtube.com/watch?v=rHqKBAHsiAo&feature=youtu.be This should be an easy print, standard PLA at usual settings will do. These don't need any specific settings for strength, 0.8mm walls and 10% infill should do the trick.