two science q's

I have two questions for you science-y types out there. I can't find a good way to Google or Wikipedia this, and asking wmtc readers is my third choice for random factual information.

1. It is said that if you throw a coin from a great height, it picks up so much force as it falls, that it can do great damage. Where I grew up, we heard that if you threw a penny off the Empire State Building, it would bore straight through someone's skull into their brain and kill them.

If this is true, why do raindrops not bore into our skin? Rain is falling from a great height. Is it because rain is liquid so it has different properties? Then shouldn't hail kill us?

Or maybe that old story is not true?

2. Long ago, people believed in the spontaneous generation of life. The example I remember is that flies arose from rotten fruit, or that spoiled meat gave rise to maggots. Now we know that is not true.

So where do the maggots come from? (From other maggots, yes.) I mean, specifically, when a piece of flesh is rotting - whether it be a creature's untended wound or a dead animal - maggots appear and contribute to the process of decomposition. Where do the maggots come from? Where were they before? How did they "know" there was rotten meat to be eaten? Where do they go when they're finished? Why do we only see them when they are writhing around a piece of dead flesh?