Brake Pad
Brake pads are a component of disc brakes used in automotive and other applications.
Brake pads convert the kinetic energy of the vehicle to thermal energy through friction. Two brake pads are contained in the brake with their friction surfaces facing the rotor.When a brake pad heats up due to contact with the rotor, it transfers small amounts of its friction material onto the disc, leaving a dull grey coating on it. The brake pad and disc (both now having the friction material), then "stick" to each other, providing the friction that stops the vehicle.