A boy on a skateboard moving at a speed of 3 m/s drops a rock from a height of 1.2 m. A girl sitting still on top of a slide will see the rock

Estimate the schwarzschild radius (in kilometers) for a mini-black hole formed when a superadvanced civilization decides to punish you (unfairly) by squeezing you until you become so small that you disappear inside your own event horizon. (assume that the your weight is 50 kg)