1, the circumference of a graphic circle with the same area is the longest, and it can travel the farthest distance in a certain period of time, which not only saves time, but also saves a lot of oil.
2. Rolling friction resistance is smaller than sliding friction resistance, and circular wheels can reduce friction resistance and speed up.
People make the wheel into a circle and let the axle pass through the center of the circle. When the wheel rolls on the ground, the distance between the axle and the ground is always equal to the radius of the wheel. This meeting will go smoothly.
A wheel usually includes an outer ring of the wheel, spokes connected with the outer ring and a central shaft. By rolling, the wheel can greatly reduce the friction coefficient with the contact surface. If equipped with a shaft, it becomes the most important part of the car. Wheels are very useful in transportation and are one of the important inventions of human beings. Besides wheels, other round wheels include ship wheels, flywheels and so on.
Extended data:
The origin of the wheel:
The predecessor of the wheel is the wheel for making pottery. The ancients used it to make pottery in batches, which was the earliest handicraft and container of human beings. The simplest pottery wheel only needs a pair of disc-shaped wheels, and a shaft is installed between the discs, and the shaft is upright; The Potter turns the lower wheel with his feet, puts the soft mud into the upper wheel by hand, and kneads it with plastic.
Application of wheels:
1, wheels have long been used to make chariots. This kind of chariot was first used to rush into enemy lines and force the enemy to break up; It was later used as a combat platform. Chariot soldiers can stand on the chariot and throw javelins at the enemy to kill him.
2. The most common use of wheels is transportation. Before the invention of the wheel, the ancients had to carry heavy objects with the help of skids. The simplest sledge is an inclined plane, and the more complicated one will put some rolling pins under the heavy objects-this is how the ancient Egyptians piled the huge stones into pyramids.
References:
Baidu encyclopedia-wheel