The movement of a group of hairs can be simplified if we think of the group as a pendulum.
In diagram (A) the weight component (w) = mg*sin(a), parallel but reverse to velocity (v), grows when angle (a) increases. Because (w) is opposing the swing of the hair, more and more, the velocity (v) of the hair will drop.
In diagram (B), the head has a velocity upward that is shrinking. If we assume that (v)y + (v)x = (v) = constant and that (v)y = the velocity of the head, then (v)y will drop and (v)x will grow when the velocity of the head decreases, and the hair will swing out from the head.
"Codepen" - https://codepen.io/ - is a social development environment - an online code editor for developers of any skill - that allows people to write code in the browser, and see the results of it as they build. Codepen is particularly useful for people learning to code.
You can view the code for the animation at https://codepen.io/steinarV/pen/qBKPGmK
