Interesting Facts About G-Force: It Is A Measure Of Acceleration, Not Force!

G Force

G Force

The g-force (with g from gravitational) refers to a measurement of a type of acceleration, which causes a perception of weight. Despite the name, it’s incorrect to consider g-force a fundamental force, as “g-force” (lower case character) is a type of acceleration that can be measured with an accelerometer.
The g-force acceleration experienced by an object is due to the vector sum of all non-gravitational and non-electromagnetic forces acting on an object’s freedom to move. In practice, as noted, these are surface-contact forces between objects. Such forces cause stresses and strains on objects, since they must be transmitted from an object surface. Because of these strains, large g-forces may be destructive.
Since g-force accelerations indirectly produce weight, any g-force can be described as a “weight per unit mass”. When the g-force acceleration is produced by the surface of one object being pushed by the surface of another object, the reaction-force to this push produces an equal and opposite weight for every unit of an object’s mass.
The types of forces involved are transmitted through objects by interior mechanical stresses. The g-force acceleration (save for certain electromagnetic force influences) is the cause of an object’s acceleration in relation to free-fall.
Gravitation acting alone does not produce a g-force, even though g-forces are expressed in multiples of the acceleration of standard gravity. Thus, the standard gravitational acceleration at the Earth’s surface produces g-force only indirectly, as a result of resistance to it by mechanical forces. These mechanical forces actually produce the g-force acceleration on a mass.
The upward contact-force from the ground ensures that an object at rest on the Earth’s surface is accelerating relative to the free-fall condition. (Free fall is the path that the object would follow when falling freely toward the Earth’s center). Stress inside the object is ensured from the fact that the ground contact forces are transmitted only from the point of contact with the ground.
Objects allowed to free-fall in an inertial trajectory under the influence of gravitation only, feel no g-force acceleration, a condition known as zero-g (which means zero g-force). This is demonstrated by the “zero-g” conditions inside a freely falling elevator falling toward the Earth’s center (in the vacuum), or (to good approximation) conditions inside a spacecraft in Earth orbit. These are examples of coordinate acceleration (a change in velocity) without a sensation of weight. The experience of no g-force (zero-g), however, it is produced, is synonymous with weightlessness.
In this post, we will share with you FIVE interesting and amazing facts about g-force.
1. In the absence of gravitational fields, or in directions at right angles to them, proper and coordinate accelerations are the same, and any coordinate acceleration must be produced by a corresponding g-force acceleration. An example here is a rocket in free space, in which simple changes in velocity are produced by the engines, and produce g-forces on the rocket and passengers.
2. Human tolerances depend on the magnitude of the g-force, the length of time it is applied, the direction it acts, the location of application, and the posture of the body. The human body is flexible and deformable, particularly the softer tissues. A hard slap on the face may briefly impose hundreds of g locally but not produce any real damage; a constant 16 g for a minute, however, may be deadly. When vibration is experienced, relatively low peak g levels can be severely damaging if they are at the resonance frequency of organs or connective tissues.
3. Aircraft pilots (in particular) sustain g-forces along the axis aligned with the spine. This causes significant variation in blood pressure along the length of the subject’s body, which limits the maximum g-forces that can be tolerated. In aircraft particularly, vertical g-forces are often positive (force blood towards the feet and away from the head); this causes problems with the eyes and brain in particular.
4. The highest recorded G-force experienced by a human who survived was during the 2003 IndyCar Series finale at Texas Motor Speedway in the 2003 Chevy 500 when the car driven by Kenny Bräck made wheel-to-wheel contact with Tomas Scheckter’s car. This immediately resulted in Kenny’s car impacting the catch fence that would record a peak of 214 G-force.
5. The human body is better at surviving g-forces that are perpendicular to the spine. In general when the acceleration is forwards (subject essentially lying on their back, colloquially known as “eyeballs in”) a much higher tolerance is shown than when the acceleration is backward (lying on their front, “eyeballs out”) since blood vessels in the retina appear more sensitive in the latter direction.

Leave a Reply, No Login Necessary.