How do disc brakes operate to slow down a vehicle?

Disc brakes operate primarily through the principle of friction, which is crucial for slowing down a vehicle. In a disc brake system, when the driver presses the brake pedal, hydraulic pressure is generated in the brake lines. This pressure causes calipers to clamp the brake pads against a rotating disc (or rotor) that is connected to the wheel.

As the brake pads make contact with the disc, friction is created between them, converting the kinetic energy of the moving vehicle into thermal energy. This process effectively slows down the rotation of the disc, and consequently, the wheels, bringing the vehicle to a stop. The efficiency of disc brakes and their ability to dissipate heat make them a preferred choice for modern vehicles, particularly in situations where consistent stopping power is required, such as during high-speed braking or heavy-load conditions.

The other options do not accurately describe how disc brakes function. Utilizing air pressure to push the wheel does not apply to the operation of disc brakes, nor does applying electrical force or locking the wheels provide the necessary mechanism for deceleration in this braking system.