To find the coefficient of kinetic friction for a 5kg block being pushed up a 20-degree incline with a force of 120N at constant velocity, it's essential to analyze the forces acting on the block. Since the block moves at constant speed, the net force is zero, indicating that the applied force equals the sum of the gravitational component and frictional force. The discussion emphasizes that mechanical energy is not conserved due to friction, which dissipates some energy as heat. Participants express confusion about using conservation of energy principles for this problem, suggesting a focus on work and energy instead. Ultimately, the problem requires careful consideration of forces and energy dissipation to find the coefficient of kinetic friction.