How does the car's kinetic energy change if you increase the speed from 50 km/h to 100 km/h?

If the car's speed changes, the kinetic energy changes **quadratically** in relation to the speed change. A speed increase from 50 km/h to 100 km/h will multiply the kinetic energy four times (*2 to the power of 2 is 4*).

If the kinetic energy is multiplied by four, braking distance is also multiplied by four, as braking distance is directly proportional to kinetic energy.