Consider a system made of a ramp that has a run of 6 m and a rise of 5 m. Two equal masses of 4-kg are connected to each other by a massless string pulled tight across a massless pulley: one block rests on the slope of the ramp and the other block hangs from the pulley without moving or touching anything. The system, therefore, is at rest. What is the force of friction (in N) acting on the block resting on the ramp? Round your answer to the nearest whole number.