Airbag deployment in a ZT

[Avulon]

Originally Posted by bl52krz

' An acceleration figure less than zero is correctly termed deceleration ?How can that be? If the figure is zero, you are not moving. Therefor there is no movement?For decelerate to take place you have to be moving? If you throw an object up in the air, it accelerates from the motion you have given it. When it reaches the top of its travel, slowly decelerating,, it stops. It then accelerates back towards the area from where it came. It does not deccelerate ?

The acceleration from the standstill has a direction. And yes in order to be decelerating you do need to be moving to start with in a specific direction, moving in the opposite direction is not decelartion. But apparrently I am "wrong" So I'll just throw physics and newtons laws of motion out the window and see them fall up to the sky....

P.S Just realised that you think that zero acceleration means not moving. It doesn't. Zero accleration means that you are maintaining a steady velocity (direction and speed) (which may or may not be a speed of 0). However you have to be doing some velocity to actually decelerate. starting from 0 and going in a direction would be to accelerate in that direction. Throw a ball up (let's say while standing on the Earth) it accelerates initially, then decelerates to a stop, and then accelerates back the other way, all due to the weakest of natural forces - gravity.

PPS - my first PS might have also misunderstood you. as reading your paragraph again you do seem to grasp the concept of decelerating to a stop and then acccelerating in the opposite direction. sorry.

Originally Posted by rockerbox

Avulon, you are wrong.

Counter evidence? - or should I just say that you are a blue martian subversive? I've got letters after my name as well..... so what? I've got enough friends with arts degrees..........

No, I've decided that you must be the Mekon and I am Dan Dare... Now Where did I park Anastasia? I need to go and sort out that horde of zombie vampire robot ninjas about to invade the Earth......

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[Avulon]

Originally Posted by rockerbox

Acceleration, which is a function of speed with time, to be accurate.

And for any pedants out there, yes, you have acceleration in negative figures.

Oh, that contribution. Look the 'rocket scientists' out there might find it useful to speak in terms of negative acceleration, but that doesn't make it 'correct' in the English language.

Also very inefficient, so much easier to say or write deceleration than negative acceleration - just look at the syllable and letter count.

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[Avulon]

C'mon someone - say you've snorted out your coffee or misdunked a hobnob already.

[Sonic ZS]

I'm trying to cut down on caffeine and not keen on hobnobs, but if airbags deploy at around 1000mph (rather than 200), I guess they've gone the way of broadband - superfast !!

[marinabrian]

Originally Posted by Sonic ZS

I'm trying to cut down on caffeine and not keen on hobnobs, but if airbags deploy at around 1000mph (rather than 200), I guess they've gone the way of broadband - superfast !!

Mmm, HobNobs, I'm away to fill the kettle

Have a look at the rather boring description of the SRS operation in the attached PDF while I make a steaming mug of coffee

Brian

[Avulon]

Originally Posted by Sonic ZS

I'm trying to cut down on caffeine and not keen on hobnobs, but if airbags deploy at around 1000mph (rather than 200), I guess they've gone the way of broadband - superfast !!

What I actually said was they deploy when the decleration is in the region of 1000mph/s - that means a deceleration equivalent to 1000-0 mph in a second Hitting a stationery 38 ton truck at any decent speed (i.e. above 20mph) is likely to make your car's front end do that. (assuming you don't just slip under the truck!

Originally Posted by marinabrian

Mmm, HobNobs, I'm away to fill the kettle

Have a look at the rather boring description of the SRS operation in the attached PDF while I make a steaming mug of coffee

Brian

Thanks Brian , I'll save it for Monday when I'm at work . Anyhow it's now 10 to scotch'o'clock must off and unlock the spirits..... Coffee's what you drink after your really???-mary (spiced vodka and tomato juice) in the morning isn't it (before work?)?

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[Avulon]

Ok, I poured a scotch then read it. - I don't see 'negative acceleration' mentioned once, I wonder why?

However on a brighter note I did spot '... preset deceleration limit...' Unfortunately that preset limit isn't quantified.

Right'o, my missus is back tomorrow and I've still got a season and a half of Battlestar Galactica left to watch before I have to relinquish control of the tv.... It's gonna be a long night.

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[2.2-600-vtec]

OK is it not that the airbag sensor is bassicly always measuring g force. So when we are moving or not g force is present unless at a set speed with no other factors or stationary. You hit some thing or something hits you the this causes a shift in weight of the g sensor this as you say is the acceleration (of the sensor only to make life easier as it's regardless of vehicle speed) that rate of acceleration of the sensor created by impact creates a g force and thus if it's at the right amount the unit pulses the airbag directly in front off the impact and job done.
Speed of the car is not a factor it's Purely the rate of direction change of the srs sensor.
Hence going of when hit stationary.
I don't know if the op was intreasted in the rest or not but that's as simple I guess as I can do and no doubt the most technical I can do

Sent from my SM-G901F using Tapatalk

[rockerbox]

A simple physics lesson for the ones among us who have addled their brains with alcohol and 70's bad science fiction:

http://www.physicsclassroom.com/mmedia/kinema/pvna.cfm

This should explain the concept, and indeed the very existance, of negative acceleration.

[Christopher Price]

It's always been my belief that the car has to experience a force in excess of 3G in order to set off an air bag.