In the inclined pulley system, block A has a mass of 10kg and experiences kinetic friction with a coefficient of 0.20 on a 30-degree incline. Since block A slides down at a constant speed, the forces acting on it are balanced, indicating that the gravitational force component down the incline equals the frictional force plus the tension in the rope. To find the mass of block B, one must analyze these forces and apply Newton's second law. The constant velocity implies that the net force on block A is zero, allowing for a direct relationship between the masses and forces involved. Understanding these dynamics is crucial for solving the problem effectively.