Quote:
Originally Posted by tuccillo
Consider a wall and two golf carts collide into the wall from either side at 20 MPH. The wall doesn't move. Each cart has the same amount of damage. Now remove the wall and have the carts collide head-on at the same 20 MPH. You will have the same effect. Two cars colliding head-on have twice the energy of one car running into a wall but with the head-on collision you have two cars damaged. One car running into a wall does not have to travel at 40 MPH to experience the same damage as if it had a head-on collision at 20 MPH. Now do you understand?
|
"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.
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.