Pick up a tiny asteroid and drop it from 1m. It hit the ground slightly faster than a reversing truck.

Pick up a bigger one and drop it from orbit it’s going to go faster.

Whatever you drop won’t be an asteroid because it’s already on earth.

So if you pick up corsica and drop it on florida from less than a meter up (they had it coming) there would be a mass extinction in florida. Everything under corsica would die, buried under a mass of rock, mud and whatever. If it did not die already because it could not squeeze into the less than a meter gap between the masses. There would also be an earthquake, maybe a tsunami if some of it fell in the ocean.