The Coefficient of friction means the ratio of friction to normal power. What is the safe’s coefficient of kinetic friction on the bank floor? The overall Clyde and Bonnie’s power on the safe is 718 N. Their total force would be 718+x (x meaning friction force). Then, 718+x is 0. The friction magnitude equals 718 N. Normal force = 9.8*323 = 3165.4 N. Coefficient of kinetic friction = 718/3165.4 = 0.227.