Thank you for all the replies!
"It's not the fall that kills you..." got me thinking. Could sliding on the ground like on the motorcycle example be considered a collision over a really long distance? Or does a collision necessarily mean head-on impacts?
I found the following formula...
The context is going down a hill in rollerblades: when people fall and they come to a quick stop (due to not having protective gear and there being lots of friction), they always end up with major injuries, while people with protective pads can sometimes fall and slide for 60+ feet and often be...