The physics of cycling: what forces does a cyclist overcome?

The bicycle is becoming an ever more popular means of transport in our day, when there are so many cars that they get in each other's way. Bicycles have numerous advantages over cars, and therefore in many European countries are considered almost the main means of getting about. The popularity of two-wheeled friends is growing in our country too. A bicycle is not only a means of transport but also a complex mechanical system that works by the fundamental laws of physics. All bicycles, regardless of type, make, model and price, make their riders overcome various forces. While riding, a cyclist encounters two main forces – gravity and aerodynamics. The force of the Earth's attraction presses the cyclist with his vehicle to the ground. The vector of the force's action is directed strictly perpendicular to the surface of the ground. The force of gravity is greater the heavier the bicycle weighs together with its rider. It has a great influence on the effort the cyclist has to make when riding his two-wheeled vehicle. If the mass of the body and the weight of the bicycle are less, riding will be much easier, and so riding will give more pleasant sensations. Although, for some people a bicycle is an exercise machine for burning calories. The second fundamental physical force that a cyclist has to overcome while moving is aerodynamics. In essence, this is the force of resistance of the oncoming air flow, which grows as the speed of movement increases. The faster the cyclist moves, the greater the force of air resistance. Besides oncoming air flows, crosswinds can also act on the bicycle, which complicates the movement still further and forces one to apply additional force. Overcoming aerodynamic forces when riding at high speed on a level road is not easy - it takes excellent physical fitness. If there is none, it is better to buy a bicycle with an electric drive, which allows riding in two modes - mechanical and automatic. It should be noted that riding in mechanical mode uses much more energy and effort than in automatic mode. To save battery charge, it is better to ride on the electric drive not all the time but only on those stretches that are especially hard to overcome under one's own power (uphill climbs, rough terrain and so on).

Published: 15.07.13