The Use of the Airbag and how it works

The purpose of an airbag is to help passengers prevent or reduce injury when the car collides or stops abruptly. Serious injuries and even death may occur where and when there are no airbags to protect passengers. Therefore, it is necessary to have airbags in all automobiles for the following reasons:

Every object has momentum. Momentum is the product of a passenger's mass and velocity ( speed with a direction). In order to stop the passenger's momentum he or she has to be acted on by a force. In some situations the passenger hits the dashboard or windshield which acts as a force stopping but injuring him or her at the same time.

An airbag provides a force over time. This is known as impulse. The more time the force has to act on passengers, to slow them down, the less damage caused to them.

There is a restricted amount of time that the airbag has to act between the moment the car hits an object and the time the passenger hits the steering wheel. About 15 to 20 milliseconds after the collision occurs the crash sensors decide whether or not the collision is serious enough to inflate the airbag (usually 6 - 10 km/h). If the crash sensors decide to inflate the airbag it will be deflated at about 25 milliseconds after the crash. It takes about 20 milliseconds to inflate the airbag for the person to land on. Around 60 milliseconds the person has made contact with the airbag and the airbag now starts to deflate. The passenger continues to be acted on by the airbag as it is in the deflation process which takes about 35 to 40 milliseconds.

All automobiles must be equipped with airbags. In addition, it is still necessary to wear seatbelts because of the following reasons:

• The crash sensors do not signal for the airbag to inflate unless the vehicle is moving at least 6km/h. Thus, a passenger can still suffer injuries from a collision at a lower speed. This is where the seatbelt plays an important role.
• The airbag, located in the steering wheel, does not protect the passenger when the vehicle is hit on the side or at the rear side.

With improvement in technology, side airbags and head airbags are being introduced in addition to the steering wheel airbag and the passenger airbag.