The weight of the car can have a significant impact on the braking distance when traveling at 20m/s. A heavier car will require more force to slow down and come to a stop, resulting in a longer braking distance. This is because the kinetic energy of the vehicle is proportional to its mass, and more energy must be dissipated to stop a heavier car. Additionally, a heavier car may require more distance to come to a complete stop due to the increased momentum it possesses.