If you fell out of a plane without a parachute, how long would it take to fall 5 miles or 8 kilometers?

Start with this formula, and work it out:

d=1/2at^2

d, distance, a, acceleration due to gravity, t, time. Solve for t given a and d.

142 seconds?

Um Terry, this formula would have you whistling with a sonic boom pretty quick. You would need to include the opposing resistive force due to the air, thereby greatly increasing the fall time.

Since the resistive force is dependent on the air density (and if you have your arms out) it becomes a bit difficult. This is where physicists usually start saying "assuming the person is approximately spherical...". ;)

You may have to take terminal velocity into consideration & give two answers as 5 miles = 8.04672 kilometres https://en.wikipedia.org/wiki/Terminal_velocity

In free fall, you fall at about 125 miles per hour (mph) if you have your arms and legs extended, and at that speed you will travel about 12,000 feet in one minute.


http://science.howstuffworks.com/question729.htm

So 12000ft per minute. Roughly 26500ft in a mile. Just over 2 minutes to go splat? Is that right?

5280 feet per mile.

Acceleration curve has to be accounted for.

If you REALLY wish to know ALL about this.....

Check out SOTHC's posted site. Too much for mathematical abilities!

Yes, if you are just looking for a rough estimate it would be a bit over 2 minutes...

We need to know wind speed and other things to figure it out.