Mechanical energy is conserved during the swinging process as long as the friend continues to swing back and forth without stopping. The discussion highlights the relationship between potential and kinetic energy, emphasizing that energy remains constant in the absence of external forces. If the swing were to stop, energy would be lost due to damping effects. The equations provided illustrate the calculations for kinetic and potential energy in the context of swinging. Overall, the conclusion is that mechanical energy is conserved while swinging at the lake hangout.