I was doing some thinking last night, then it occurred to me. We are trying to do simulations of crashes using linear motion. Dropping a helmet vertically. That’s linear.
For sure, it’s a good-enough approximation when you hit something head-on… or is it? If you come off and fly through the air, then maybe, you’ll strike something dead-level.
More probable though, is you’ll follow an arc, under projectile motion. The most likely scenario is that as the bicycle/motorcycle tilts over, you follow it. It’s not going to be a direct-to-the-ground vertical drop of your head, but rather, a circular arc.
So how do we test for it? I suppose like this: