新聞說有個人跳降落傘,點知開唔到,但係佢無跌死?

The person probably has landed on bushes with soft soil, or landed on surfaces covered with thick snow.

The speed of the person before hitting the ground depends on the height at which he jumps. Suppose the person reaches a speed of 100 km/h (=28 m/s) before touching the ground, and assume a person is of mass 60 kg and could tolerate a decceleration of 3g, say (i.e. 3x10 m/s2), then

the momentum of the person before hitting the ground = 60 x 28 Ns = 1680 Ns

For a decceleration of 3g, the net force acting on the man is = 60 x 3g N = 180g N = 1800 N

The decceleration time = 1680/1800 s = 0.9 s

That is, if the person collides with trees and bushes and eventually lands on soft soil, the duration could be as long as 1 second. In that case, he wouldn't be killed provided that he is able to tolerate the 3g decceleration.

一句講晒，佢既terminal velocity 唔係好大。咁樣佢撞落地面的rate of change of momentum 唔足以整死佢