Just so there is no confusion, I am addressing the statement that a cart has to run into a wall at 40 MPH to sustain the same (roughly) damage as if it had a head-on collision with another cart at 20 MPH. This is not true. When two carts at 20 MPH collide, the same amount of energy has to be dissipated as if they both ran into a wall at 20 MPH. The wall will absorb a small amount of the energy but the vast majority will be absorbed by the carts (plus some goes into sound and heat). Twice the energy, twice the number of carts, same damage to each cart, same as if the cart ran into a wall by itself at 20 MPH. Of course, there is a fundamental, and I assumed obvious, assumption that we are talking about a "substantial" wall. One that remains intact after the collision.
I will do the mathematical proof but I am not sure anyone will follow it.
Quote:
Originally Posted by Polar Bear
"same effect"...because you say it is so that makes it so? Pretty big assumption there.
How about this...
Scenario 1 - A wall is moving along at 20 MPH and hits a stationary wall.
Scenario 2 - Two walls are moving toward each other, each going 20 MPH, and collide.
The intensity of the impact for both scenarios is exactly the same? I don't think so. Now do you understand?
Look, I know what you're saying. And I don't disagree with you as much as it might appear. The problem is we're comparing apples and oranges. One has walls with zero energy absorption. Another has vehicles with who-knows-how-much energy absorption. But comparing the two is similar to saying the damage of two vehicles colliding head on is similar to one of them driving off a certain height cliff, or being near an explosion, or something else...again...apples and oranges. But relative velocity at impact is the velocity that matters in a collision. After that is when you start considering other factors such as energy absorption, energy distribution, etc.
|