Car's airbag deployment system. Let's discuss the math! I'm trying to explore the concepts and/or Calculus/Physics behind auto airbag deployment...  I am assuming the computer feeds real time velocity points and the ECU is monitoring for a sudden drop in rate of change / sudden spike in negative acceleration? 
Does this seem correct? Can we try to describe what the algorithm is looking for?   ACU is fed constant speed values from the speed sensor. ACU can calculate acceleration based on time elapsed b/w 2 speed data points.
The following is just 8th grade Algebra, and I know actual ACU systems will be much more nuanced (side impact, etc), but is this the core idea involved?
VELOCITY
$$t=(milliseconds), s=(mph)$$
$$t=0, s=55$$
$$t=5, s=60$$
$$t=10, s=70$$
$$t=15, s=50$$
$$t=20, s=0$$
At time=20 the car has hit into wall and stopped suddenly!
ACCELERATION
Let's calculate some rate of change of velocity using $\frac{\delta Y}{\delta X}$:
$$\frac{60-55}{5-0}= 1 mph$$
$$\frac{70-60}{10-5}= 2 mph$$
$$\frac{50-70}{15-10}= -4 mph$$
$$\frac{0-50}{20-15}= -10 mph$$
During some interval, maybe the airbag is triggered once the acceleration exceed some negative threshold ?
Does this seem reasonable?

It is more complicated than that.  They probably have 3 axis measurements of acceleration and angular acceleration, so can trigger on a side impact (where the forward velocity doesn't change much) and a rear impact (where the acceleration is unrealistically positive).  They also read very frequently so they can filter to avoid triggering on one bad reading.
