Brake pads are engineered to produce friction. The job of the braking system is to convert kinetic energy to heat, which is responsible for slowing the vehicle down. Each time you press the brake pedal, the brake fluid will push out the pistons in the brake caliper. This, in turn, will press the brake pads against the brake disk so you can stop safely without much fuss or drama.
When it comes to automotive brakes, there are two general types of friction: abrasive and adherent friction. Abrasive friction is produced when the friction material of the brake pad is in contact with the disc directly and the rubbing action between the two results in a break-down (at the molecular level) of both pad and rotor. In other words, an abrasive system wears both pad and rotor simultaneously.
On the other hand, adherent friction is a phenomenon that occurs when the pad leaves a trace layer of material on the surface of the disc and then is rubbing against that. Thus, apart from the time it takes for the pad to heat up and develop a thin layer on the disc, the pad is never really contacting the metallic rotor surface directly. This causes the pads to wear at a faster rate without much wear on the rotor.
In the case of the Challenger, which sports ceramic pads as standard equipment, both abrasive and adherent friction is used. At lower temperatures, the braking action is caused primarily by abrasive friction. Once the pads are warm, however, adherent friction takes over.
The brake pads and the brake disks are not entirely responsible for the stopping performance of a Dodge Challenger – the tires play an important role in braking action as well. Alas, the topic of having the right set of tires is best reserved for a separate discussion.