But we want revolutions. Put your feet on either side of a doorway and stand with your nose and stomach touching the door edge. Try to stand up on your tiptoes. Explain, using the idea of center of mass, why you can't do this. When you stand on your tiptoes, your center of mass moves forward.
High heels are less stable than flat heeled shoes, and tiptoes are less stable than flat feet.
In heels or on tiptoe, your base of support is much smaller than it is with your whole foot flat. Your center of mass is also a bit forward of where it is used to being, which means that all those little adjustments you naturally make when moving are a bit off-center and you have to actually think a bit more about it all. Book problem 12-23. The woman is 1.7 meters long. Let's pick our unknown x from her feet.