You run out of the door and outpace the zombies by a large margin as you head down the forest path toward the helicopter. Stopping only to check the map occasionally, you make good time. However about halfway to the helicopter, a tiny, hairy hand snatches the map from your back pocket. You turn around and see a group of evil zombie weasels! You pull out your pistol, but the weasels hide behind the map. You will have to find a way to scatter them.

You find a large rock. If you throw the rock horizontally at a speed of 50m/s from 1m above the ground, how far away should you be in order for the rock to land on the weasels? Note that the zombie weasels have a bizarre antigravity field, reducing gravitational pull in the area to 8m/s^2.