00:01
In part a, we're asked to find the acceleration during the crash.
00:04
The first thing to do is convert 311 kilometers per hour into meters per second.
00:09
To do this, we multiply by the conversion factor.
00:13
1 ,000 meters and one kilometer.
00:16
This will cancel the kilometers and leave us with meters.
00:19
And then we want to cancel the hour so they go in the numerator.
00:23
We want to turn them into seconds, and one hour is 3 ,600 seconds.
00:29
When we multiply this out, we'll get 86 .4 meters per second.
00:37
Now, in order to determine the acceleration, let's write down our gnomes.
00:44
Our y minus y not, the distance traveled during the deceleration is negative 0 .81.
00:53
Our initial velocity is negative 86 .4 meters per second.
01:02
Our final velocity is going to be zero because it comes to a rest.
01:06
In order to find the acceleration, we're going to use vy squared is equal to v0 y squared plus 2 times the acceleration in the y direction times the distance traveled in y minus why not.
01:21
This yield 0 is equal to 7 ,465 plus 2 times the acceleration with respect to y times negative 0 .81.
01:32
Solving this for the acceleration with respect to y, we get 4 ,608 meters per second squared.
01:42
And then we can divide this by 9 .8 in order to get in terms, terms of gs.
01:47
When we do that, we get that's equal to 470 gs.
01:59
And that's the end of part a.
02:03
Part b asked for the force exerted during the process.
02:07
And so we're going to use the sum of the forces in the y direction is equal to mass times acceleration in the y...