Extreme physics:How can i stop a bike with just my fingers?
The work is all done by the brake pads, not your fingers. They hydraulics amplify the force from your fingers. For all practical purposes, none of the bikes motion energy gets transferred to the brake levers. The reason you have to pull the levers so far is that the system isn’t perfectly rigid. Certain things in the system flex when the hydraulic pressure increases, like the hydraulic hoses, the brake calipers, the pads compress a bit, the hydraulic fluid itself compresses a bit, requiring some amount of fluid to be pumped into the system to accommodate the flexing. This translates into work that your fingers have to do(force times displacement). Almost all the work for stopping the bike gets translated into heating the pads and disc(some of the work is used to grind your pads and disc into dust). You could increase the amount of amplification, making the pistons on the lever side smaller and the brake side bigger or lengthening the levers, but this would increase the amount of displa
In the disc brakes to stop the wheel, friction material in the form of brake pads (mounted on a device called a brake caliper) is forced mechanically, hydraulically, pneumatically or electromagnetically against both sides of the disc.The brake caliper is the assembly which houses the brake pads and pistons.The most common caliper design uses a single hydraulically actuated piston within a cylinder, although high performance brakes use as many as twelve. Modern cars use different hydraulic circuits to actuate the brakes on each set of wheels as a safety measure. The hydraulic design also helps multiply braking force. The number of pistons in a caliper is often referred to as the number of ‘pots’, so if a vehicle has ‘six pot’ calipers it means that each caliper houses six pistons.
