A solid, uniform cylinder with mass 8.35 kg and diameter 17.0 cm is spinning with angular velocity 230 rpm on a thin, frictionless axle that passes along the cylinder axis. You design a simple friction-brake to stop the cylinder by pressing the brake against the outer rim with a normal force. The coefficient of kinetic friction between the brake and rim is 0.344.
What must the applied normal force be to bring the cylinder to rest after it has turned through 5.40 revolutions?