Reply to thread

Message: <blockquote data-quote="Blacksad" data-source="post: 153995" data-attributes="member: 1359">It's a shock, so the Energy doesn't have the time to be immediatly released in heat or anything else at first, the kinetic energy  is a good approximation in this case. I haven't missed it, but it's inaccurate.let say you go from 200m/s to 50m/s in 1s, it's effectivly a 150m/s*s acceleration, and you continue to go forward.let say you go from 50m/s to -50m/s in 1s, it's effectivly a 100m/s*s acceleration, and you go backward.the first acceleration is the worst to the human body. the link you gave say the opposite. also it use a wall as the innert object and not a car of similar mass in the example, so it tends to modify the results.[edit]ie if the wall is elastic the car will keep all the energy if it is plastic (I don't know if it is the correct term in english), half of the energy will be released in the wall.[/edit]and yes I agree that a simple rule is better than an equation, but when a simple rule can be used to reflect reality, I feel it is better.</blockquote>