Depends on how far you want to take it, and what kind of bike it is. The most common type of light weight bike is probably a road bike, and they are generally equipped with caliper rim brakes, with single-pivot being the lightest design available.
But there are also light weight MTBs, and they generally run disc brakes. A MTB for flat terrain can still have straight-pull brakes(v-brakes), which is a kind of rim brake too. They can still be lighter than disc brakes although braking isn't quite as good.
Alloy brakes refer to bicycle brakes that are made from aluminum alloys, which offer a good balance of strength, durability, and lightweight characteristics. These type of brakes are commonly found on entry to mid-range bicycles.
Brakes!
For use on the public roads/areas YES that is a legal requirement.
Brake blocks is an earlier name for brake pads for caliper brakes on bicycles. The blocks/pads that clamp to stop the bike.
Brakes help a bicycle to stop, of course --- but do you know why? it's because brakes use friction. When you squeeze the brakes, rubber blocks press against the wheels. The friction between the blocks and the wheels slow your bicycle down.
Road bicycles.
Inspired Bicycles sell mountain, BMX and trial bikes along with brakes, clothing, frames, seating, handles and miscellaneous merchandise. These products can all be ordered online for delivery.
In the 1950's and early 60s Sears bicycles were sold under the name " J.C. Higgins" (perhaps a jab at their competitor J.C. Pennys?). For a while in the later 60's and early 70's, they only bore the "Sears" name. During this time, many of their "lightweight" bicycles were manufactured by Puch bicycles from Austria, and were of very high workmanship. About 1973 Sears began offering Huffy bicycles under the name "Free Spirit".
Possible to stick them on - yes, on some bicycles. Flat bar bicycles have a grip area diameter of 22.2 mm (7/8") which I believe is the same that motorcycles use. Getting them to work well with bicycle brakes - unlikely. Hydraulic MC brakes push a lot more fluid than bicycle hydros. For cable, the pull / leverage is unlikely to play well with what bicycle brakes expect.
A brake shoe is the part of a braking system which carries the brake lining in the drum brakes. It can be used in automobiles, bicycles, and other things.
skin
Disc brakes