MECHANICAL BRAKES
Mechanical brakes have levers or cables that force one or two pads against the wheel. Most bicycles have two mechanical brakes called calliper brakes, one for each wheel. Each brake has two small rubber pads, one on each side of the wheel rim. The pads are mounted on a mechanical device that is connected to one end of a long cable. The other end of the cable is connected to a lever on the handlebar. When the rider squeezes this lever, force on the cable presses the pads against the wheel rim.
Cars are equipped with another kind of mechanical brake called an emergency brake or hand brake. This brake is also known as a parking brake because it helps prevent a parked car from rolling away. When the driver applies the hand brake, a system of levers, rods, and cables applies pressure to the pads or shoes of the rear wheels.
