# G Force?

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#### fatal291

##### Guest
Hey I was just wondering what are some good examples or comparisons on G Force? (Motion/ Gravity) I attempted to do some research on this myself but I am pretty sure I screwed up some where when trying to understand the everyday uses and effects of G Force. I know this may be a stupid question to most of you but I would like some results thanks.

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#### enigma10

##### Guest
Flying high! <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>

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#### bonzelite

##### Guest
roller coasters. <br /><br />

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#### CalliArcale

##### Guest
Well, to get you started, G force is a measure of acceleration, not gravity. 1 G is defined as equivalent to the acceleration applied to a body on Earth at sea level (on average) by Earth's gravity alone.<br /><br />Where is this measurement useful? Well, it is useful in describing gravitational fields, but in day-to-day use it is more useful in describing acceleration of other things. Acceleration technically is *any* change in velocity and/or direction of travel -- you experience it when you turn as well as when you speed up or slow down. (Slowing down is negative acceleration, or deceleration.) You hear it mentioned a lot in roller coasters (as bonzelite already mentioned), race cars, and fighter jets.<br /><br />Right now, sitting quietly at your computer, you are experiencing 1 G of acceleration straight downwards. Since your chair and the floor are in the way, you do not actually fall but are pressed against your chair, exerting a force equivalent ot your body weight. (Weight is actually a measure of force, not mass.) This 1 G of acceleration is approximately 9.8 meters per second squared (if I am remembering correctly). If you get in an elevator which goes upwards very fast, you will feel as if you are being pressed down against the floor even harder. You are experiencing 9.8 m/sec2 from the Earth, plus whatever acceleration the elevator is exerting as it speeds up. For the few seconds that it is accelerating (before the elevator settles to a constant speed), you will therefore feel heavier. if you are standing on a scale, you will even be able to measure exactly how much heavier.<br /><br />Roller coasters use the wildly changing track to change your direction of travel so that you experience Gs other than 1 -- including Gs less than 1. As the train screams down a hill, without any brakes, you will approach 0 G -- weightlessness. Then as it hits the valley and abruptly begins climbing again, you will feel more than 1 G, making you feel much heavier. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

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#### search

##### Guest
Hello<br /><br />First the definition:<br /><br />http://dictionary.laborlawtalk.com/g-force<br /><br />Now the examples:<br /><br />Fighter pilots: when they fly they are subjected to acceleration forces which are described as g-forces. They have actually a g-force meter (or g-meter) which enables him to access many of the maneauvers. Imagine a 176lb/80kg pilot. If the g-meter is showing 1g it means the pilot is experiencing a force equivalent to his own weight 176lb/80kg or the same you are experiencing sitting at the computer. If the g-meter shows 9g it means he is now feeling his own weight equivalent to 9x176lb/80kg or 1584lb/720kg. Thats quite some weight... <br /><br />Rollercoasters: if you have been in one you have felt the g-forces and they normally go up to 3g so maybe you felt like 3x(your own weight).<br /><br />Speedcars (Indy and F1): Same as above the pilots can sustain up to 5g in some curves during the races. Here the problem is that this g-force are transversal which means instead of being applyied from your head to feet like in most maneauvers of fighter planes the force is normally a centrifugal force which sends you away from the curve.<br /><br />Hope its enough<br />

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##### Guest
As an everyday event I read somewhere when you 'plonk' down on a chair you experience 10<i>g</i>

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#### fatal291

##### Guest
hello what can i compare g force to? you know like when youre in a car and you turn onto a highway ramp, is that g force u feel as you turn? how much force is it? im just looking for a way to compare gforce to something i use everyday like an elevator or car ride.

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#### agnau

##### Guest
I believe the term g-force to be a misnomer.... I usually see it in reference to multiples of earth's gravity. So "5g"s would be 5*earth's gravity.<br /><br />More important though, we are probably referencing the acceleration that is that multiple and all the stresses on a body that would accompany that.

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#### nexium

##### Guest
While race car drivers sometimes accelerate at about 3/4g, speeding up, slowing down and turning, typical road cars are in danger of a wreck even at 1/4g. Neil

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#### derekmcd

##### Guest
The force you are referring to with the vehicle is a Centrifugal force. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

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#### fatal291

##### Guest
oh i read some where that plopping down into a chair is equal to 2Gs is that true?

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#### derekmcd

##### Guest
I guess that would depend on how tall you are and how short the chair is. The distance you 'plop' would effect the amount of force you feel. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

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#### Mee_n_Mac

##### Guest
<font color="yellow">im just looking for a way to compare gforce to something i use everyday like an elevator or car ride. </font><br /><br />A force that's equal to the force gravity provides is said to equal "1g". An acceleration of 64.4 ft/sec/sec would be said to equal 2g's (F=mA). So "g's" are just another unit of measurement of a force or an acceleration, depending on the user's intent. Relating to everyday use like a car, you have 1g holding you to the seat in the vertical direction while just sitting there. Hard cornering in a good sports car might produce an additional lateral force of something around 0.9 g's. Stomping on the ABS brakes will produce a similar force and that's one you can test yourself, though hopefully not everyday. <img src="/images/icons/smile.gif" /><br /><br />If you are really interested there are fairly inexpensive electronic meters you can buy for you car that will measure and display the lateral and/or longitudinal forces. They also give you 0-60 mph and 1/4 mi times by integrating the forces they measure. They cost around \$100. If you want to make one yourself, well here's some plans to do so. <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

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#### emperor_of_localgroup

##### Guest
The formula you can use is speed v=.68*sqrt(32.2*Radius). The answer is in mph. 'Radius' of the loop or the ramp curve is in feet. The number .68 is to convert speed from ft/sec to mph. With this speed you will feel 1g force. See, the pic, these highway loops have radius of approximately 200 ft. That means if you drive at 55mph around this highway loop, you will feel 1g froce sideways. If you want to feel 2g, multiply 32.2 in the formula by 2, etc. <br /><br />Now go use the formula and make donuts in the parking lot.<br /> <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

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##### Guest
Of course, unless your tires have a coefficent of friction greater than 1, the force you feel will be your car leaving the pavement and rolling through the weeds.

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##### Guest
Plopping is more like 10g<br />Flat out braking in your car should give 1g although high hyteresis in tyres can improve slightly on that.

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#### docm

##### Guest
<blockquote><font class="small">In reply to:</font><hr /><p>While race car drivers sometimes accelerate at about 3/4g, speeding up, slowing down and turning, typical road cars are in danger of a wreck even at 1/4g. Neil<p><hr /></p></p></blockquote><br /><font color="yellow"><b>Grossly off!!</b></font><br /><br />on/in a drag bike or dragster;<br /><br />Acceleration: 4 - 5 G's (as in 0-60 in ~0.7 seconds for bikes)<br />Braking: 4+ G's (parachute)<br />Cornering: not applicable - straight line racing.<br />Wreck: see F1 cars<br /><br />in a Formula 1 car the max forces are;<br /><br />Acceleration: 2.0 - 2.2 G's<br />Braking: 5+ G's<br />Cornering: 4 - 5 G's<br />Wreck: highest survived - 179 G's; David Purley in 1977 @ Silverstone; 173 km/h (108 mph) to 0 in a distance of 66 cm (26") after his throttle jammed wide open & he walled. He lived, but was never the same. Some up to 300+ G's and they don't survive.<br /><br />and for high-performance street cars (A/B/C limited by DOT-legal tires);<br /><br />Acceleration: 0.9 - 1.2 G's (also gearing dependent)<br />Braking: 0.8 - 1.3+ G's<br />Cornering: 0.9 - 1.5 G's<br />Wreck: up to 300 G's, but 10 - 30 is more common<br /><br />Low performance cars? Let's put it this way; even an old Datsun 510 sedan can pull .6 G in both cornering and braking, and they had rubber bands for tires <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> </div>

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