How Does an Air Bag Utilize Physics to Save Lives?

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Discussion Overview

The discussion centers around the functioning of air bags in vehicles, exploring the physics principles involved, particularly in relation to Newton's laws of motion. Participants are considering how to effectively explain the mechanics of air bags, including their components and the forces at play during a collision.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Homework-related

Main Points Raised

  • One participant describes the components of an air bag, including the bag, sensor, and inflation system, highlighting the chemical reaction that produces gas for inflation.
  • Another participant suggests a reasoning approach based on Newton's laws, explaining how an air bag reduces acceleration and force experienced during a collision.
  • There is a mention of the relationship between impulse and maximum force, indicating a consideration of how air bags manage forces during impact.

Areas of Agreement / Disagreement

Participants have not reached a consensus on how to best explain the workings of air bags, with varying approaches suggested, including technical descriptions and applications of Newton's laws.

Contextual Notes

Some participants express uncertainty about the depth of knowledge required for their responses, indicating a potential gap in their understanding of the physics involved in air bag operation.

Who May Find This Useful

This discussion may be useful for students learning about the application of physics in real-world scenarios, particularly in automotive safety and the principles of motion and force.

daisy_polly
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Hi,

How does an air bag work?

I know a lot about how an air bag work as I am a physics grade11 student but I am confused how to really answer the question.Should I answer it techanically or use Newtons law to answer it.


Thanks in advance.
An early reply is appreciated.
Daisy.
 
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airbag

There are three parts to an air bag. First, there is the bag itself, which is made of thin, nylon fabric and folded into the steering wheel or the dash board. Then there is the sensor that tells the bag to inflate. It detects a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 kph).

Finally, there is the inflation system. Air bags are actually inflated by the equivalent of a solid rocket booster. Sodium azide (NaN3) and potassium nitrate (KNO3) react very quickly to produce a large pulse of hot nitrogen gas. This gas inflates the bag, which literally bursts out of the steering wheel or dashboard as it expands. About a second later, the bag is already deflating (it has holes in it) in order to get out of your way.


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thanks

Thanks!:smile:

how should I answer the question as my teacher is not actually teaching us all that about the air bag but gave us this question.
We are learning about Newtons laws.
 


Originally posted by daisy_polly
how should I answer the question as my teacher is not actually teaching us all that about the air bag but gave us this question.
We are learning about Newtons laws.
Try this line of reasoning: When you crash, your speed is changing from X miles per hour to zero. Thus you are being accelerated, which means a force is being applied to you. Without the airbag, you smack into the dashboard which brings you to a stop rather quickly---high acceleration, high force: not good! The airbag slows your acceleration---lower acceleration, lower force: good!

Make some sense?
 
Thanks so much for your help.
 
Same impulse; different maximum force.
 

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