Why are wheels made round? Give it to me!

Why are the wheels round? You may say that this is not an easy question, because round wheels can roll! This is a good statement, but it is not always very convincing, because it is only based on our feelings and experience, and does not find the root cause from the nature of the circle.

What are the important properties of circles? We can find a compass to draw a circle, and the point where the cone is tied when drawing a circle is called the center of the circle. Let's take a ruler and measure the distance from any point in the circumference to the center of the circle, they are all equal. This equal distance is the radius.

If the wheel is made round and the axle is placed in the center of the circle, the distance of the axle from the ground is always equal to the length of the radius of the wheel when the wheel rolls on the ground. Therefore, the person sitting in the car will be smoothly pulled by the car. Suppose that the wheel is deformed, it is no longer round, and the rim is one higher and one is lower, that is to say, the distance from the rim to the center of the wheel circle is not equal, then this kind of car must be very bumpy when driving.

When did people come to know the nature of circles? Originally, it was nature that inspired people that the sun in the sky and the moon of fifteen were all round! From here, people learned about the image of a circle and began to learn to draw it.

Later, people learned from practice that the radius of a circle is equal, and the compass was invented to draw circles.

The plane profile of the wheel is circular, and the center of the axle is placed on the center of the circle by taking advantage of the property that the radius of the circle is equal. When the wheels are rolling on the ground, the distance between the axle and the ground is always equal to the radius of the wheels, so as long as the road is flat, the car will drive smoothly on the ground.

Some say triangles.

And quad tires can also roll, but we all know that in terms of comfort, it must be round and more comfortable. From a scientific point of view, there are the following reasons:

From a mechanical point of view:

1. Made into a circle, the wheel is rolling on the ground, the resistance is very small, the center of gravity of the car is in a straight line, and only need to provide power to overcome the rolling friction.

to get the car moving.

2. If you change to other shapes, it will inevitably move the center of gravity of the car up and down, and moving up and down requires external force to provide power, so that a lot of force is wasted.

3. It is the most labor-saving to make it round.

1. Analysis of the learning situation.

Students' knowledge and skills: Students have already learned about the circle in elementary school. Students have learned about the properties of circles through origami, symmetry, rotation, etc., accumulated some understanding of circles, possessed the basic skills of drawing circles and calculating their perimeters and areas, and understood the basic knowledge that circles are axisymmetric and center-symmetrical figures.

Basis of student activity experience: In the learning process of related knowledge, students use the formula of the circumference and area of the circle to solve some simple practical problems, feel the use of the formula, and gain the importance of mathematical knowledge in daily life and learning.

2. Content Analysis:

Although primary school students have an understanding of the relevant knowledge of circles, they have not yet abstracted the concept of "the distance from the plane to the fixed point is equal to the fixed length of all the points composed of the figure called the circle". The position relationship between the point and the circle is studied, and the position relationship between the point and the circle is judged by the distance from the point to the center of the circle.

3. Teaching Objectives:

1.Go through the process of forming the concept of the circle and refine the concept of the circle;

2.Through the process of exploring the position relationship between points and circles, understanding the position relationship between points and circles, and using the combination of numbers and shapes to judge the position of points and circles on the plane.

3.Through exploration, students can improve their expression skills, experience the practical application of circles, feel the close connection between mathematics and real life, and enhance students' awareness of mathematics application.

4. Teaching focus: understand the definition of a circle, and be able to accurately judge the position relationship between a point on a plane and a circle.

Teaching difficulty: Understand the definition of a circle from the perspective of a set, and understand the position relationship between points and circles.

5. Teaching and learning methods: Teaching methods: problem guidance, inspiration and pointing, using geometric drawing boards to make dynamic courseware; Learning method: autonomy, cooperation and communication, make full use of group learning.

6. Teaching process:

Session 1: Create a Scenario.

Why are wheels round? Is it OK to make wheels in other shapes?

When the wheel is rounded, the distance from each point on the wheel to the wheel axis o during rotation is equal to the radius of the wheel. The distance between the axis and the smooth road surface remains the same when the wheels are rolling, so the person who sits in the car will feel very stable and comfortable, which is the mathematical reason why the wheels are made into circles, and the wheels made into hexagons are unstable. )

Design intent]: Introduce topics from common life phenomena, stimulate students' learning curiosity, and guide students to draw the concept of circles.

Session 2: Definition of perception (key content).

It is unfair to stand in this way, because the distance between the students and the circle is not equal, and they should stand on the same circle at an equal distance from the object, so that the students can perceive the circle.

For in the case of equal sides of length, the circumference of the circle is the longest; The distance from the center of the circle to the points around the circle is equal; It is also because the rolling friction resistance of the circle is the least; Therefore, the wheels are rounded, which can make the car run smoothly and quickly.

Because circles can be rolled, triangles and squares cannot.

It should be that the radius of the circle is equal for each strip.

Because the center of the circle is a line while driving.

The distance from the center of the circle to any point outside the circle is equal.

Because the radius of the circle is equal (within the same circle).

The round wheels can roll, and the round tires roll comfortably.

Because the circle rolls fast, the force point is the same.

Because it hits and stabilizes Tieguanyin, there is the sun every day.

The contour of the wheel plane adopts the property that the radius of the concentric circles is equal, and the center of the axle is fixed. When the wheels roll on the ground, the distance between the axle and the ground is always equal to the radius of the wheel, so as long as the road is flat, the car will drive smoothly on the ground.

In fact, it can also be made into a square, there is no special requirement, you just like it personally.

It can make the car drive stably, and it will not go up and down when driving like a triangle.

Because of the wheels, the wheels, of course, the car has to be driven and the wheels that have to roll, only the round wheels can roll.

If it doesn't make a circle, is it okay to go?

The wheel is made round because: the length of the arm is always equal during rotation, as long as the force driving the wheel is controlled, the output force of the wheel can be controlled. When the circular wheel rotates to any angle, the distance from the center of the circle to the ground is constant, and the vehicle will not jump up and down.

The contour and fixed radius of the sleek ruler determine that it is very smooth when rolling, and there will be no fast and slow situations.

In fact, not only circles, but also many other shapes of objects can be rolled on the ground, such as ellipses, polygons, and so on. However, the characteristics of different objects when rolling are completely different, and only the characteristics of the circle are the most suitable for our needs when transporting heavy objects.

Summary. Hello, the reason why the wheels are designed to be round, there are two main reasons, which are labor-saving and smooth, because the wheels are designed to be round, which can reduce frictional resistance during driving, and the axle rolls on the ground through the center of the circle, so that the driving will be more stable. <>

Why are wheels made round?

Hello, the reason why the wheels are designed to be round, there are two main reasons, which are labor-saving and smooth, because the wheels are designed to be round, which can reduce frictional resistance during driving, and the axle rolls on the ground through the center of the circle, so that the driving will be more stable. <>

<> make the wheel round, the axle is installed in the center of the circle, when the car wheel rotates, the distance between the axle and the ground is always equal to the radius of the wheel, so that the driving will be more stable, because the carriage is installed on the axle of the car, only the wheel in the state of smooth operation, the carriage will be more stable. <>

There are two main reasons why the wheels used in cars are designed to be roundThey are labor-saving and smooth.

1. The distance from the center of the circle to any point on the circumference is equal, and this equal distance is called the radius, when the wheel rolls on the ground, the distance of the axle from the ground is always equal to the radius of the wheel, so that the driving will be stable and will not produce bumps.

2. The round wheel can reduce the friction with the ground in the process of driving, improve the acceleration, and improve the work efficiency of the car.

If the wheel hub of the car is deformed due to some fault reasons, and the distance from the tire to the central axle is not equal, the car will not be stable during driving.

Circles have the property that the distance from the center of the circle to any point in the circumference of the circle is equal, and this equal distance is called the radius. That is to say:

In the same circle, all the radii are equal. "So, people made the wheel round and made the axle pass through the center of the circle, and when the wheel rolled on the ground, the distance from the ground was always equal to the radius of the wheel. If the wheel is deformed, not round, and the distance from the rim to the center of the wheel is not equal, then this kind of car will definitely bump up and down, how can it move better?

Of course, the wheels are made round because the rolling friction is smaller than the sliding friction.