A golf ball with a mass of 46g is hit from the ground with a speed of 20m/s. It takes that ball 1 second to reach its highest point. For all parts assume that the air resistance is negligible. The system includes the golf stick, golf ball, and Earth. I created an energy bar chart attached below. The part where I'm getting stuck is figuring out what is doing the negative work. At first I thought it was the Earth but it can't be because it is part of the system. Then I started doubting my energy bar chart. The final Ug would be mgh so I did m=0.046(covert from g to kg), g=-10, and h=5(figured out using kinematics). The Ug would then be -2.3. But wouldn't it have to be positive 2.3 for energy to be conserved? But at the same time, how can it be positive; g is always negative? So please clear up this problem, I've been stressing on it too much.