# 請問人類跳傘時，於降落傘未張開時的終端速大約為何??

Update:

R=D*空氣密度*A*V^2/2

D為經驗值

A為截面積

V為速度

R為空氣阻力

Rating

我不會算, 但是給你一個參考值.

Capt. Joe W. Kittinger achieved the highest parachute jump in history on August 16, 1960 as part of a United States Air Force program testing high-altitude escape systems. Wearing a pressure suit, Capt. Kittinger ascended for an hour and a half in an open gondola attached to a balloon to an altitude of 102,800 feet (31,330 m), where he then jumped. The fall lasted 4 minutes and 36 seconds, during which Capt. Kittinger reached speeds exceeding 700 miles per hour. The air in the upper atmosphere is less dense and thus leads to lower air-resistance and a much higher terminal velocity.

(wiki)

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我想要比他快也很少有了.

你的問題不好解, 因為只有空氣密度是已知數, 就算已經有

速度 V, 但是人的截面積的變動很大, 很難估算. 然後衣服的

材質/造型對D(drag)的影響很大.

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這裡有另外的說明:

Terminal velocity is often reported to be approximately 60 m/s for a typical skydiver in free fall. Exceptional skydivers are able to increase this value considerably by diving head first with their arms against the sides of their bodies, legs held firmly together, and toes pointed. This posture presents a minimal projected area perpendicular to the direction of motion thus reducing aerodynamic drag. Special helmets and slick body suits reduce drag even further.

而且,他還說道

The density of air at 30 km is roughly 1.5 % that at sea level and thus drag is essentially negligible. ... This is not true for skydivers at ordinary altitudes, which is why they reach terminal velocity and cease to accelerate...

http://hypertextbook.com/facts/JianHuang.shtml

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有用到的公式:

R=D*空氣密度*A*V^2/2

D為經驗值

A為截面積

V為速度

R為空氣阻力

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