# G-force

The gravitational force, or more commonly, g-force, is a measurement of the type of acceleration that causes a perception of weight.wikipedia
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### Accelerometer

accelerometersG-sensoracceleration sensor
Despite the name, it is incorrect to consider g-force a fundamental force, as "g-force" is a type of acceleration that can be measured with an accelerometer.
Such accelerations are popularly denoted g-force; i.e., in comparison to standard gravity.

### Weightlessness

zero gravityzero-gravityzero-g
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).
Microgravity (or µg) is used to refer to situations that are substantially weightless but where g-force stresses within objects due to tidal effects, as discussed above, are around a millionth of that at the Earth's surface.

### Proper acceleration

physical acceleration
His weight (a downward force) is 725 N. In accordance with Newton’s third law, the plane and the seat underneath the pilot provides an equal and opposite force pushing upwards with a force of 725 N. This mechanical force provides the 1.0 g-force upward proper acceleration on the pilot, even though this velocity in the upward direction does not change (this is similar to the situation of a person standing on the ground, where the ground provides this force and this g-force).
In an accelerating rocket after launch, or even in a rocket standing at the gantry, the proper acceleration is the acceleration felt by the occupants, and which is described as g-force (which is not a force but rather an acceleration; see that article for more discussion of proper acceleration) delivered by the vehicle only.

### Specific force

Specific force is another name that has been used for g-force.
Specific force (also called g-force and mass-specific force) is measured in meters/second² (m·s −2 ) which is the units for acceleration.

### G-suit

anti-G trousersanti "G" flying suitanti-g
A typical person can handle about 5 g0 (meaning some people might pass out when riding a higher-g roller coaster, which in some cases exceeds this point) before losing consciousness, but through the combination of special g-suits and efforts to strain muscles—both of which act to force blood back into the brain—modern pilots can typically handle a sustained 9 g0 (see High-G training).
A g-suit, or the more accurately named anti-g suit, is a flight suit worn by aviators and astronauts who are subject to high levels of acceleration force (g).

### Standard gravity

gacceleration due to gravityacceleration of gravity
One g is the acceleration due to gravity at the Earth's surface and is the standard gravity (symbol: g n ), defined as 9.80665 metres per second squared, or equivalently 9.80665 newtons of force per kilogram of mass. Note that the unit definition does not vary with location—the g-force when standing on the moon is about 0.181 g.
is also used as a unit for any form of acceleration, with the value defined as above; see g-force.

### Roller coaster

roller coastersrollercoasterroller-coaster
A classic example of negative g-force is in a fully inverted roller coaster which is accelerating (changing velocity) toward the ground.
The accelerations accepted in roller coaster design are generally in the 4-6Gs (40–60 m s −2 ) range for positive vertical (pushing you into your seat), and 1.5-2Gs (15–20 m s −2 ) for the negative vertical (flying out of your seat as you crest a hill).

### High-G training

centrifugecentrifugeshuman centrifuge
A typical person can handle about 5 g0 (meaning some people might pass out when riding a higher-g roller coaster, which in some cases exceeds this point) before losing consciousness, but through the combination of special g-suits and efforts to strain muscles—both of which act to force blood back into the brain—modern pilots can typically handle a sustained 9 g0 (see High-G training).
It is designed to prevent a g-induced loss of consciousness (G-LOC), a situation when the action of g-forces move the blood away from the brain to the extent that consciousness is lost.

### G-LOC

blackoutblacked outblack out
A typical person can handle about 5 g0 (meaning some people might pass out when riding a higher-g roller coaster, which in some cases exceeds this point) before losing consciousness, but through the combination of special g-suits and efforts to strain muscles—both of which act to force blood back into the brain—modern pilots can typically handle a sustained 9 g0 (see High-G training).
G-force induced loss of consciousness (abbreviated as G-LOC, pronounced 'JEE-lock') is a term generally used in aerospace physiology to describe a loss of consciousness occurring from excessive and sustained g-forces draining blood away from the brain causing cerebral hypoxia.

### Redout

red outredouts
This condition is sometimes referred to as red out where vision is figuratively reddened due to the blood laden lower eyelid being pulled into the field of vision Negative g is generally unpleasant and can cause damage.
A redout occurs when the body experiences a negative g-force sufficient to cause a blood flow from the lower parts of the body to the head.

### Greyout

grey outgrey-outgray out
Grey-out, where the vision loses hue, easily reversible on levelling out.
A greyout may be experienced by aircraft pilots pulling high positive g-forces as when pulling up into a loop or a tight turn forcing blood to the lower extremities of the body and lowering blood pressure in the brain.

### Weight

gross weightweighingweigh
The gravitational force, or more commonly, g-force, is a measurement of the type of acceleration that causes a perception of weight.
It is actually the sensation of g-force, regardless of whether this is due to being stationary in the presence of gravity, or, if the person is in motion, the result of any other forces acting on the body such as in the case of acceleration or deceleration of a lift, or centrifugal forces when turning sharply.

### Thrust-to-weight ratio

thrust to weight ratioThrust/weightlow weight
If there are no other external forces than gravity, the g-force in a rocket is the thrust per unit mass. Its magnitude is equal to the thrust-to-weight ratio times g, and to the consumption of delta-v per unit time.
In general, the thrust-to-weight ratio is numerically equal to the g-force that the vehicle can generate.

### Metre per second squared

m/s 2 meters per second squaredm/s²
One g is the acceleration due to gravity at the Earth's surface and is the standard gravity (symbol: g n ), defined as 9.80665 metres per second squared, or equivalently 9.80665 newtons of force per kilogram of mass. Note that the unit definition does not vary with location—the g-force when standing on the moon is about 0.181 g.
Acceleration can be measured in ratios to gravity, such as g-force, and peak ground acceleration in earthquakes.

### Free fall

free-fallfreefallhighest fall without a parachute
The g-force acceleration (except certain electromagnetic force influences) is the cause of an object's acceleration in relation to free fall.
G-force

### Rocket

rocketsrocketryrocket scientist
If there are no other external forces than gravity, the g-force in a rocket is the thrust per unit mass. Its magnitude is equal to the thrust-to-weight ratio times g, and to the consumption of delta-v per unit time.
This, for example, allows minimization of aerodynamic losses and can limit the increase of g-forces due to the reduction in propellant load.

### Gravitron

Alien AbductionG-Force AcceleratorStarship 4000
At this speed, the riders are experiencing centrifugal force equivalent to three times the force of gravity.

### Red Bull Air Race World Championship

Red Bull Air RaceRed Bull Air World RaceAir Race
Exceeding 10g for more than 0.6 seconds

### Sprint (missile)

SprintSprint missileSprint anti-ballistic missile
Sprint accelerated at 100 g, reaching a speed of Mach 10 in 5 seconds.

### Space gun

space cannongun launchgun-launched
The large g-force likely to be experienced by a ballistic projectile launched in this manner would mean that a space gun would be incapable of safely launching humans or delicate instruments, rather being restricted to freight, fuel or ruggedized satellites.

### Mantis shrimp

stomatopodmantis shrimpsStomatopoda
In smashers, these two weapons are employed with blinding quickness, with an acceleration of 10,400 g (102,000 m/s 2 or 335,000 ft/s 2 ) and speeds of 23 m/s from a standing start.

### Space Shuttle

Shuttlespace shuttlesSpace Shuttle Program
Acceleration at this point would typically fall to .9 g, and the vehicle would take on a somewhat nose-up angle to the horizon – it used the main engines to gain and then maintain altitude while it accelerated horizontally towards orbit.

### Saturn V

SaturnSaturn V rocketC-5
Including gravity, launch acceleration was only 1¼ g, i.e., the astronauts felt 1¼ g while the rocket accelerated vertically at ¼ g. As the rocket rapidly lost mass, total acceleration including gravity increased to nearly 4 g at T+135 seconds.

### Shock (mechanics)

shockmechanical shockImpact shock
In the case of a shock, e.g., a collision, the g-force can be very large during a short time.
g-force

### Bugatti Veyron

VeyronBugatti Veyron Super SportBugatti Veyron 16.4
Bugatti claims maximum deceleration of 1.3 g on road tyres.