So, last week I discussed the Physics of a car crash and how the force of a crash on a person’s body is interesting because it depends more on the speed and time of deceleration, versus the size of the car. (…The size of the car is important too, but for this argument we just wanted to point out the inner system impact).
I explained that the force of a car crash or collision on a passenger or driver can be determined by the Gadd Severity Index, which determines the impact of the crash.
This post is going to attempt to explain how to measure the force of a collision on the car or vehicle that’s experiencing the collision.
In order to determine the strength of the force against a car, we’ll need to determine the kinetic energy. This website gave a great illustration that allows you to plug in your own numbers to prove the equations.
So, if the initial KE = 1/2mv^squared and the resulting force it take’s to stop a car = fd=-1/2mv^squared. In order to find the force, you would need to know the measurements for the distance the car moved after the collision, i.e. did it slide 3 meters forward? And secondly, what is the mass and speed of the car before the collision?
Once these terms are determined, the equation is easy to move around… f = -1/2/mv^squared. This explanation of force is also a great illustration for how potential and kinetic energy interact.
When the car was speeding forward, it was relying on kinetic energy. When the car suddenly stopped against a pole or a tree, it was exhibiting potential energy. Remember, all energy is conserved, therefore– work output = work input and fd output = fd input (or vice-versa).
I hope this second section gives a general idea of how force can be measured from a car crash. Next week we’ll be looking at the Physics of a ponytail.
Physicsfromapicklejar... 