A 1500 kg car skids to a halt on a wet road where μk = 0.51. how fast was the car traveling if it leaves 66-m-long skid marks?

We got coefficient of friction uk = 0.51

Mass m = 1500 kg

normal force on the car = weight of the car = 1500 * 9.8 N = 14700 N

and the force of friction on the car, f = uk * normal force = 0.51 * 14700 N = 7497 N

taking Acceleration a = - f/m = - 7497/1500 = - 4.998 m/s^2

Displacement s = 66 m

Final velocity v = 0

Initial velocity u = ?

v^2 = u^2 + 2as

0 = u^2 - 2 * 4.998 * 66

u = 25.69 m/s