That certain change from that ecosystem will require 50 years or longer because big ecosystems need a long time to restablize the living ecosystem.
Velocity=3.4m/sec
Mass=30kg
so kinetic energy=1/2mv^2
=1/2×30×3.4×3.4
=15×3.4×3.4
=15×11.56
=173.4 kg m per second square