G-force
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The g-force or gravitational force equivalent is a mass-specific force, expressed in units of standard gravity. It is used for sustained accelerations that cause a perception of weight. For example, a
This Top Fuel dragster can accelerate from zero to 160 kilometres per hour (99 mph) in 0.86 seconds. This is a horizontal acceleration of 5.3 g. Combining this with the vertical g-force in the stationary case using the Pythagorean theorem yields a g-force of 5.4 g.
This acrobatic airplane is pulling up in a +g maneuver; the pilot is experiencing several gs of inertial acceleration in addition to the force of gravity. The cumulative vertical axis forces acting upon his body make him momentarily 'weigh' many times more than normal.
The Superman: Escape from Krypton roller coaster at Six Flags Magic Mountain provides 6.5 seconds of ballistic weightlessness.
High-g training
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High-g training is done by aviators and astronauts who are subject to high levels of acceleration. It is designed to prevent a g-induced loss of consciousness, a situation when the action of g-forces
G-force
…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 (88 m/s2) (see High-G training). In aircraft particularly, vertical g-forces are often positive (force blood towards the feet and away from the head); this causes problems with the…
The 20 g centrifuge at the NASA Ames Research Center
TsF-18 centrifuge at the Yuri Gagarin Cosmonauts Training Center