A vehicle is moving at a speed of 12 m/s on a level road. It applies emergency brakes and starts to skid without rolling in a straight path. The deceleration of the vehicle is constant after braking and it comes to rest at a distance of 15 m. Assuming, g=10 m/s², the coefficient of kinetic friction between the tyres and road is ________. [round off to 2 decimal places]