1. The problem statement, all variables and given/known data Hey! Problem: A ball falls 8,5 meters, and hits the ground with 11 m/s. The ball has a mass of 0,2 kilos. How much work was done by Air resistance on the ball? 2. Relevant equations I guess mechanical energy eqution? 3. The attempt at a solution answer should be -4,5 joule? I think. I came to 70 or something. Someone help?