This is more complicated that you folks seem to think it is. You should not rely on intuition except for qualitative comparisons of various objects. Without some established formulae, you cannot get good numeric answers.

Doing calculations including atmospheric effects is a difficult task. Even if you assume no wind, constant density at all altitudes, and a constant amount of water vapor in the atmosphere, it does not seem easy. In a vacuum, it is easy to calculate final speed at impact with the Earth. For an object with no initial velocity

- Distance = Acceleration * Time<sup>2</sup> / 2

Acceleration = Approximately 32 Feet / Seconds<sup>2</sup> or 980 cm / seconds<sup>2</sup>

Time = SquareRoot( 2 * Distance / Acceleration )

Speed = Acceleration * Time

Speed = SquareRoot( 2 * Distance * Acceleration )

I hope I did the above correctly. The acceleration is actually a variable, but the above is a good approximation for objects falling from less than ten miles above the earth. A reference book I have gives 32.1725 & 980.621 at sea level and 45 degrees latitude. I did a few calculations and rounded the results.

- From 5000 feet: 122 MPH

From 10,000 feet: 550 MPH

From 20,000 feet: 770 MPH

From 5000 meters: 1127 km / hour

The above are for falling in a vacuum.

I have heard estimates of 125 MPH as the maximum for a human body, but do not know what assumptions are made about being tucked up or spread eagled. The clothing (if any) would make some difference.

The falling penny is a very difficult problem. The lower estimate of 35MPH and the higher estimate of 65MPH are not the difference between falling flat or edge down. It is due to different assumptions about how the penny changes orientation as it falls. Falling exactly edge down is a theoretical possibility like the possibility of balancing a needle on its point. Edge down, I would expect a penny to fall faster than a human body. Note that a penny would not fall straight down. When it was at a angle with the veritical, it would have a horizontal component of velocity. It might tumble.

The TV program was debunking a myth about a penny tossed from a high building and killing somebody when it hit them in the head. It said nothing about a bullet fired upwards and hitting somebody when it descended. In a vacuum, it would impact at muzzle velocity if fired straight up, but I have no idea about the atmospheric effects.

I am not sure how a bullet would fall. I suspect that it would fall nose first after the first few hundred feet, but am not sure about this.

I was hoping that some body here knew formulae or a URL leading to some real information.