G-force can be defined as the computation of the kind of force per unit mass that generates a perception of weight. Though it is called g-force it has an SI unit similar to that of acceleration which is meters per second square (m/s2). This is because g-force isn’t really a force, it is a term used in general physics to measure the force of gravity acting on a particular object. The conventional value of a force equal to one G, where G is referring to g-force is equivalent to gravitational acceleration on Earth which is 9.8 meters per second square. The amount of g-force acting on an object can be determined by calculating the vector sum of all the non-gravitational and non-electromagnetic forces restricting that object’s freedom to move. Though a feeling of g-force can be perceived during multiple applications of free-fall acceleration, however, objects that are free-falling in an inertial trajectory just under just the influence of gravity experience no g-force at all. This phenomenon in physics is known as zero-g. This phenomenon of zero-g also helps prove the fact that g-force cannot be produced by just the force of gravity acting on an object, and that it requires a mechanical force to produce it. G-force is a scalar quantity which means it can only be described by its magnitude and not by the direction of motion. Despite g-force not being a vector quantity, positive g-forces point in the downward direction, and negative g-forces point in the upward direction. The reason behind this oddity is that g-force is considered to be a vector of acceleration.
Airplanes were the first instrument to be developed that could accelerate at insurmountable speeds that no human had ever seen or experienced before. During the World War I period, plenty of airforce pilots suddenly started losing consciousness and cognizance during flight time. This situation resulted due to the extensive amount of g-force experienced by the pilots while dogfighting with their jets. It became a serious concern for pilots and doctors; in the year 1919, a doctor termed this strange phenomenon as “fainting in the air”. which was quite literally the crisis at hand. With the development of newer technology, planes with faster speeds and more mobility were produced, making g-force even more dangerous. Studying all the cases of airforce pilots and their rates of survival during crashes, it became a conventional norm that a pilot’s threshold to being exposed to g-force is up to eighteen Gs. Therefore, improved cockpits were invented to withstand a force up to eighteen Gs, but many pilots managed to survive crashes with an estimated g-force much bigger than what was devised safe.
Human tolerance of the g-force primarily depends on the following factors, the magnitude of the gravitational force, the time-period, the vector direction, the point of contact, and finally, the posture of the body. A solid slap on the cheeks or a punch to the stomach may temporarily inflict hundreds of gs at that particular tissue surface but may not inflict any real damage, while on the other hand, a constant force of sixteen Gs for a time-period of an entire minute, may be fatal. Moreover, an immediate force of seventy-five Gs can kill a person instantly. An airforce pilot making steep turns in a fighter jet experiences a force much greater than just the force of gravity. The acceleration of a military fighter jet or a high-performance aircraft can cause an acceleration of up to nine Gs whereas, astronauts while taking off in space shuttles experience just around three to four Gs. The highest recorded Gs experienced in a space shuttle was in the year 2008 when sixteen crewmembers of a Soyuz spacecraft encountered more than eight Gs before landing. G-force can also be experienced in cars, for example, every formula one car is fitted with an Accident Data Recorder which is a device that records speed and g-force. The average g-force experienced by a formula one driver is two Gs while accelerating, five Gs while braking, and four to six Gs while making a turn or cornering. Furthermore, amusement park rides like the roller coaster can accelerate at speeds fast enough to encounter an unexpected amount of g-force. The roller coaster named “Tower of Terror” located in Gold Reef City park in Johannesburg, Gauteng, South Africa, in the year 2001, was ranked number one for the highest amount of g-force experienced on a rollercoaster. The reported g-force was a whopping 6.3 Gs, and it still holds its record.
G-force is a very common and at the same time a lethal phenomenon that can be experienced by a person in his day-to-day life. After years of research, the phenomenon mentioned earlier, “fainting in the air” is now known as blacking out or greying out. This happens because, as an airplane makes steep turns, all the fluids in the pilot’s body act like they are in a centrifuge and travel towards the body’s outermost part or towards the body part that is on the outward perimeter of the turn. This results in the brain and eyes suffering from a lack of blood and also oxygen via the blood. Lack of blood and oxygen to the eyes causes dizziness, a grey out, which is an immediate loss of color vision, or even a full blackout that is temporary blindness. The pilot might also experience tunnel vision which means the extremities of the eyes get blurred. Blacking out and losing cognizance for a fighter pilot around fifty thousand miles above sea level can be very dangerous. All of these phenomenons can be critical considering how important reflexes can be for an airforce pilot. To cope with situations like these, airforce pilots need to go through intense training where they are trained to fight back during these circumstances because one wrong move or even a loss of vision can result in a do-or-die situation for the pilot. Pilots are taught special maneuvers to help them during these situations, for example, if a pilot feels tensed up while in the air, they are instructed to hold their breath in short bursts and pull against it, which makes the head feel a little buzzy. This maneuver helps in restoring blood flow to the brain, which helps prevent blacking out and have a clear vision. Nowadays, pilots wear special g-suits that are developed to withstand tremendous g-force and are also equipped with a blow-up bladder mechanism. The blow-up bladder is a mechanism that is clamped to the lower part of the suit and in case of an emergency where the pilot experiences a loss of blood to the upper body, the mechanism forces blood back up through the pilots’ body.
G-force can be an extremely dangerous force that can be experienced while accelerating at high speeds. It is very common to experience g-force and can even be endured while performing an everyday activity like driving. Undergoing a high amount of g-force suddenly can be life-threatening. Being exposed to g-force for a long period of time can be lethal and someone who is undergoing g-force every day, like an airforce pilot should take precautionary measures to avoid any permanent damage. To conclude, this paper talks about what is g-force, what are its common applications, human tolerance of g-force, and how to minimize the effect of g-force.
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Fin.