As the penny falls 320 meters, its vertical velocity increases at the rate of 9.8 m/s each second. Use the following equation to determine its speed when it hits the ground.
vf^2 = vi^2 + 2 * a * d, vi = 0
vf^2 = 2 * 9.8 * 320
vf = √6272
This is approximately 79 m/s. I hope this helps you to understand how to solve this type of problem.