You are in a zombie-themed paintball shooting range, armed

Last updated: 7/31/2022

You are in a zombie-themed paintball shooting range, armed with a spring-loaded paintball gun. The spring mechanism, with a spring constant of 8.6 x 104 N/m compresses 1.5 cm in order to shoot out a 3.0 gram paintball. You are at the bottom of a set of stairs and see a zombie pop up at the top of the stairwell. If the zombie is located a vertical distance of 15 meters above you, with what speed does the paintball hit the zombie? Ignore air resistance.