In general, there are sensors mounted on the frame of your car to detect rapid acceleration (or deceleration). These sensors will trigger the release of compressed gases contained in a bottle that rapidly inflates the airbags.
It depends on your car and model if the air bags will deploy if the car's engine is off but the air bags are still activated as long as it is still connected to the battery.
a car with air bags
it will fit but you have to put air bags suspension on the car for it to work.
a godly car A big car with air bags.
that car has air bags in the rear so either the air bags are bad or the air pump on lines are bad
Nylon bag.
No, however, it does mean the air bags won't work if there is an accident
Not that I know of. Never heard of aftermarket SRS.
air bags and seatbelts.
Zero to as many as ten.
If your car does not have air bags, yes - your insurance will be more expensive, all other things being equal. To put it simply: If you have air bags, that's a discount.
Yes, you can die in a car crash. Seat belts and air bags have greatly reduced the number of deaths from car crashes. Seat belts only work if they are fastened.