Final answer:
Hard braking causes weight to shift to the front of the vehicle, increasing traction on the front tires and potentially reducing it on the rear tires, which could lead to a loss of control or skidding.
Step-by-step explanation:
Sudden or hard braking results in a weight transfer to the front of the vehicle and a possible loss of traction to the rear tires. When a driver applies the brakes suddenly or forcefully, the momentum of the vehicle causes the weight to shift toward the front. This can compress the front suspension and unload the rear suspension. As a result, the front tires will gain more traction while the rear tires may lose some, which can potentially lead to a loss of control or skidding, especially if the vehicle is rear-wheel drive.