In terms of impulse, why does an airbag reduce injuries?
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My guess would be that in a crash something is going to stop you. the force of the air bag will be more evenly distributed though.
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Absorbs shock.
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OK ready. . . Impulse is the integral of force over time and is measured in Newton seconds. . . eg. . one newton of force over one second will change the momentum. . . a force of 3 newtons over a half of a second, etc. etc etc... so for rigid body collisions we apply an infinite force over a very small time frame. . . this way the impluse is = the change in momentum of the colliding objects. Newtons third law applies. . . and the impulse on the colliding objects will be equal and opposite. I dont have a symbol function on this thingy so I cant write you an equation but you should ahve an impluse vector equation in your book. So when a car collides with an object it recieves X amount of force. . . which then creates a shock that travels up the elecrical system of the vehicle (depending on what type of system it is) and releases an airbag.. this occurse over an infantecimal amount of time. . . x amount of force/ time creates this reaction. . along with the general reaction of either coming to a complete halt or bouncing back. INSIDE THE CAR: an object in motion stays in motion. When the car collides it comes to a halt, in some cases it hits so hard that it bounces back in the direction it came at the collided object. When the airbag is deployed due to this collision the individual driving the car is still moving forwards. The airbag basically inflates for the sole purpose of absorbing the impact of the still moving body inside the car. Upon impact there are seams on the side of the airbag which burst and deflate. Firstly absorbing the impact and secondly deflating so that the person has room to breathe and hopefully walk away from the accident. As far as impulse theory goes there are two stories to discuss. .. the initial impact of the vehicle, and the impact of the individual driving onto the airbag, and you could possibly argue the force of the individual being pushed back into their seat after the airbag deploys. . .but they probably arent looking into too much detail with that. Impulses have similar laws to forces. . because they are time integral forces. . .(forces over time f/t) every impulse has an equal and opposite impulse. . . you can either do this linearly or rotating. . in your case I think the linear method is probably what you would go for .. . and you can calculate motion from an impulse if you know the initial velocity . . . The important thing in that is that the linear motion will be in the same direction as the impulse even if the impulse is applied at an offset point from the center of mass. . . its kind of counterintuitive but thats the hard part about impulses. . . I hope this helps really I need to be there and draw you a picture.