Final answer:
Depressing the brake pedal slows the vehicle by engaging the brake system and converting kinetic energy into thermal energy. It also turns on the back brake lights.The correct option is 4.
Step-by-step explanation:
Depressing the brake pedal slows the vehicle by engaging the brake system. When you depress the brake pedal, a hydraulic system is activated, which causes brake pads to press against the brake rotor or drum, creating friction that slows down the vehicle. This friction converts the kinetic energy of the moving vehicle into thermal energy, dissipating it into the surrounding environment.
The process of depressing the brake pedal also turns on the back brake lights. This is important for alerting other drivers behind you that you are slowing down or stopping.