Bicycle
Bicycle, also called a bike, is a two-wheeled steerable machine that pedals by the rider's feet. On typical bicycle wheels are mounted in-line during a metal frame, with the front wheel held during a rotatable fork. The rider sits on a saddle and steers by leaning and turning handlebars that are attached to the fork. The feet turn pedals to attach cranks and a sequence wheel. Power is transmitted by a loop of chain connecting the chain wheel to a sprocket on the rear wheel. Riding is definitely mastered, and bikes are often ridden with little effort at 16–24 km (10–15 miles) per hour — about four to five times the pace of walking.
The bicycle is the most effective means yet devised to convert human energy into mobility. Probably, many of my readers, even completely uninterested in a bicycle story, have even heard about Lance Armstrong and the doping scandal that erupted last year. Bicycles are widely used for transportation, recreation, and sport. Throughout the planet, bicycles are essential to moving people and goods into areas where there are few automobiles. Globally, there are twice as many bicycles as automobiles, and that they outsell automobiles to three at least one. Netherlands, Denmark, and Japan actively promote bicycles for shopping and commuting. Within us, bike paths are built in many parts of the country, and bicycles are encouraged by the government as an alternative to automobiles.