If the object were 10 meters across and mostly iron, I really wonder how much of it would be left when it reached the ground. At the speed those things are moving, and considering thermal conductivity, just how much of it could really vaporize before it reached Earth's surface. Look at "shooting stars" - those things are just like grains of sand to the size of rice; not big rocks, and they travel a pretty significant distance. Big, impressive ones are rare & are only the size of a golfball. Look at how long their trails are. (their trails caused by ionizing the atmosphere)
I've unfortunately never taken an astronomy course, but I'm pretty skeptical of "most of it" being vaporized before it reaches the earth. Of course, a lot depends on how obliquely it strikes the earth. But still...
Also, 10m being harmless? The Tunguska event was estimated to be from a 50m object (of course, that's 125 times the volume, but even with one 125th of the energy, that's a hell of a wallop to whatever it hits.)
Took a while of searching, but "Typically, though, a meteoroid would have to be about the size of a marble for a portion of it to reach the Earth's surface. " is the only place that seems to confirm my thoughts. (I didn't find any to the contrary) - of course, and I realize this, most larger objects break up due to the enormous pressures involved as they plunge through the atmosphere.
