I'm putting this on a shirt.

[Brenok]

I have a t-shirt that says "May the F=ma be with you" and it annoys me that read out loud it is "may the force equals mass times acceleration be with you." Where if it was just "ma" then the reader would have to figure out that "ma" means "mass times acceleration" which equals force. It's more clever that way.

Of course, then it would just say "May the ma be with you" and people would wonder if it was some kind of "yo mama" joke. So maybe the entire concept of the shirt doesn't work.

Also? Most people think it says "May the FEMA be with you" and it's a joke about Hurricane Katrina. This poor shirt just can't catch a break.

dp/dt works.

[Bill Phil]

The acceleration at the time of impact is the sudden deceleration when you hit the ground. Acceleration due to gravity will frequently be cancelled out by drag so the only relevant acceleration is when you go from whatever speed you're falling at to 0m/s in a very short space of time.

You just said what my original point was.

[Starhawk]

Given the two equations, I would say it like this:

It's not the magnitude of V_f that kills you, it's the tinyness of delta-t!

Happy landings!