Question #905da

Apr 13, 2017

It's in Newton's 2nd law

Explanation:

The force you experience during a crash is defined by Newton's 2nd law.

$F = m a = \frac{m v - \text{mu}}{t}$

Where $v$ is the final velocity and $u$ is the initial velocity. In a crash, we can assume $v = 0$ so this reduces to

$F = - \frac{\text{mu}}{t}$

Hence the force exerted on a person in a crash is a function of three things, mass, initial speed, time to come to a stop. Once a crash is initiated, there is not much you can do about u and m. However, the longer the time period over the deceleration, the less force you will experience. This is where the seat belt comes in. It stretches during a collision, increasing the time over which the force is exerted on the passenger, thereby reducing the force they experience.