<P> Unopposed acceleration due to mechanical forces, and consequentially g - force, is experienced whenever anyone rides in a vehicle because it always causes a proper acceleration, and (in the absence of gravity) also always a coordinate acceleration (where velocity changes). Whenever the vehicle changes either direction or speed, the occupants feel lateral (side to side) or longitudinal (forward and backwards) forces produced by the mechanical push of their seats . </P> <P> The expression "1 g = 7000980665000000000 ♠ 9.806 65 m / s" means that for every second that elapses, velocity changes 7000980665000000000 ♠ 9.806 65 meters per second (≡ 7000980665000000000 ♠ 35.303 94 km / h). This rate of change in velocity can also be denoted as 7000980665000000000 ♠ 9.806 65 (meter per second) per second, or 7000980665000000000 ♠ 9.806 65 m / s . For example: An acceleration of 1 g equates to a rate of change in velocity of approximately 35 kilometres per hour (22 mph) for each second that elapses . Therefore, if an automobile is capable of braking at 1 g and is traveling at 35 kilometres per hour (22 mph) it can brake to a standstill in one second and the driver will experience a deceleration of 1 g . The automobile traveling at three times this speed, 105 km / h (65 mph), can brake to a standstill in three seconds . </P> <P> In the case of an increase in speed from 0 to v with constant acceleration within a distance of s this acceleration is v / (2s). </P> <P> Preparing an object for g - tolerance (not getting damaged when subjected to a high g - force) is called g - hardening . This may apply to, e.g., instruments in a projectile shot by a gun . </P>

What is the maximum g force a human can endure