01-01-2010, 08:22 PM
Thanks TomK,
makes sense. Yes, I can tell they're complicated! One thing I read (quickly) is that if the cars bounce off each other (rebound) there is more force/kinetic energy than if they stick and crumple. I also read that force and time are inversely proportional, so that something that extends the TIME in which a crash unfolds reduces force. That is what airbags do, as do the crumple zones. In addition, when cars stick together the momentum shifts to them traveling together, which is less than when they rebound off each other, and crumple zones facilitate that. That is the gleanings of my five minutes physics research.
My remark about the stationary car came from an accident I was in many years ago. We were broadsided while entering an intersection going slowly from a full stop, hit by a pickup going 55 mph. The truck driver was fine, but our driver was injured a lot. On reflection though, probably because we were hit from the side which has less protection.
Rob, I speak of all this with the conviction that your daughter will not end up in this situation, or I wouldn't talk about it in such clinical terms. Personally I would not have the nerve to face an oncoming driver playing chicken and HOPE he makes a rational choice or -- figures out in time that the other car is not going anywhere.
So I looked up the airbags question online. It says airbags need electricity to activate. So while the engine need not be running, the ignition must be on or they will not work!
makes sense. Yes, I can tell they're complicated! One thing I read (quickly) is that if the cars bounce off each other (rebound) there is more force/kinetic energy than if they stick and crumple. I also read that force and time are inversely proportional, so that something that extends the TIME in which a crash unfolds reduces force. That is what airbags do, as do the crumple zones. In addition, when cars stick together the momentum shifts to them traveling together, which is less than when they rebound off each other, and crumple zones facilitate that. That is the gleanings of my five minutes physics research.
My remark about the stationary car came from an accident I was in many years ago. We were broadsided while entering an intersection going slowly from a full stop, hit by a pickup going 55 mph. The truck driver was fine, but our driver was injured a lot. On reflection though, probably because we were hit from the side which has less protection.
Rob, I speak of all this with the conviction that your daughter will not end up in this situation, or I wouldn't talk about it in such clinical terms. Personally I would not have the nerve to face an oncoming driver playing chicken and HOPE he makes a rational choice or -- figures out in time that the other car is not going anywhere.
So I looked up the airbags question online. It says airbags need electricity to activate. So while the engine need not be running, the ignition must be on or they will not work!