Energy plays a role in pretty much everything we do and that includes driving a vehicle. And, energy, like most things, is controlled by the laws of physics. More specifically, the energy involved in a moving vehicle is controlled by the laws of motion. To understand why this is so important, we need to look at mass and velocity. Any moving object has mass; the amount of stuff the object contains. It is a measure that is closely related to how much an object weighs.
A moving object also has velocity; speed focused on a specific direction. When an object has both mass and velocity, it also has kinetic energy. The great the mass and velocity of an object, the great the amount of kinetic energy it has. That does not become a problem until the object stops moving, either because you want to stop or because it has collided with an object.
In either case, the kinetic energy that has been built up needs to go somewhere, it does not simply disappear. So, the faster you are moving, the more difficult it is to stop and the more damage that is done to the vehicle. Most cars are now designed to absorb much of this energy during a collision. While this reduces some of the danger, it does not account for the fact that the driver and passengers are also objects that have their own mass and during the stopping motion of a vehicle, also have their own velocity.
Before airbags, the only things stopping the driver and passengers from being carried forward with continuing momentum were their seat belts. Hot blasts of the nitrogen inflate the airbag. You should always keep 5 lbs. This is where an air compressor kit comes in handy, monitoring and maintain the minimum air bag pressure.
We carry a broad selection of Ford Expedition parts and accessories designed to fit many model years. Some 50 milliseconds after an accident, the car's occupant hits the air bag and its deflation absorbs the forward-moving energy of the occupant. Sign up for our email newsletter. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue.
See Subscription Options. Fall Flash Sale. Merola, a chemistry professor and associate dean of the College of Arts and Sciences at Virginia Tech, offers this explanation: Joseph S. There are three parts to an airbag that help to accomplish this feat:. Early efforts to adapt the airbag for use in cars bumped up against prohibitive prices and technical hurdles involving the storage and release of compressed gas.
Researchers wondered:. They needed a way to set off a chemical reaction that would produce the nitrogen that would inflate the bag. Small solid-propellant inflators came to the rescue in the s. The inflation system is not unlike a solid rocket booster see How Rocket Engines Work for details. The airbag system ignites a solid propellant , which burns extremely rapidly to create a large volume of gas to inflate the bag.
The bag then literally bursts from its storage site at up to mph kph -- faster than the blink of an eye!
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