how much acceleration can a human endure
The NHTSA standard for a sudden impact acceleration on a human that would cause severe injury or death is 75 g's for a 50th percentile male, 65 g's for a 50th percentile female, and 50 g's for a 50th percentile child. These figures assume the human is taking the impact on the chest/stomach, the back, sides or the head.
Once terminal velocity (maximum acceleration, usually 120 miles per hour for average-sized humans) is reached, Doherty says, it doesnât really matter whether you throw another 5000 or 10,000 feet on top of Mageeâs 20,000: Youâre not going to fall any faster.