The actual g forces experienced by astronauts are less than predicted due to the varying conditions during different phases of flight, such as takeoff, space travel, and reentry. The standard gravitational force of 9.8 m/s² applies only when an object is at rest or moving at a constant speed. During shuttle ascent, the acceleration adds to the perceived g forces, but the net effect can be less than expected when considering the dynamics of the spacecraft. The relationship between force, mass, and acceleration (F=ma) is crucial in understanding these variations. Overall, the actual g forces depend on the specific phase of the mission and the spacecraft's acceleration profile.
