First man in space:

Joe Kittinger looks like a cowboy but he's an airforce colonel and the first man in space.

In 1960 he went up 20 miles in a helium balloon, a little silver bubble in the blackness. Half-way there his glove split, allowing deadly cold in. "I didn't tell my flight surgeoun because I didn't want to worry him. I felt reasonably certain I could survive." At 103,000 ft he said a silent prayer - it had to be silent, there was no air - and jumped.

I fell face to earth for a little ways and I really had no sensation of falling because I had no visual reference. I turned over on my back about this time and I looked up and the balloon was racing into the heavens, just flying away. What it was was the balloon was standing still and I was the one that was falling."

He fell at the speed of sound but made no sound. No air rippled his space suit. After four minutes, he reentered the atmosphere.

He hit the desert and thought it looked like the garden of Eden. Someone patted his cheek.

Uppgift:

1. Uppskatta hur mycket helium som behövs för att ballongen skall kunna lyfta med Kittinger.
2. Hur stor volym upptar ballongen på 3 mils höjd? Räcker det för att lyfta honom också på denna höjd?
3. Rita ett diagram över krafter som verkar på Kittinger och på ballongen strax för hoppet.
4. Vilken acceleration får Kittinger då han lämnat ballongen?
5. Hur stor blir ballongens acceleration då Kittinger hoppat?
6. Kittinger hoppar ut med ansiktet mot jorden, men kommer på att han vill titta på ballongen. Kan han på något sätt vända sig så att ryggen pekar mot jorden istället?

Hopp med luftmotstånd från hög höjd.

Felix Baumgartners rekordhopp 14 okt 2012.