“National Youth Robot Technology Level Examination (Level 1)” course, this series of courses takes robot-related physical mechanics, mechanical principles, basic electronic knowledge as the main content, bringing children into an interesting robot world full of technical knowledge!

What is a swing

A swing is a sports device, or a play tool, that we can see in parks, schools or communities. The child sits on the seat, pushed by others or forced by his own feet, and the person swings back and forth with the seat.

The origin of the swing

The origins of swings date back hundreds of thousands of years to antiquity. At that time, our ancestors needed to go up to trees to pick wild fruits or hunt wild beasts in order to make a living. In climbing and running, they tend to grab stout creeping plants, rely on the swing of rattan, go up trees or cross ravines, which should be the most primitive prototype of swings.

Nowadays, swings can be found everywhere in parks and communities.

Knowledge points of this course

Stability of triangles:

We can first use building blocks to build a triangle, a quadrilateral, a pentagonal, and then apply a certain force to the structure of these shapes, and observe which shape is less likely to deform?

Experiments have proved that the triangular structure is very stable and will not deform.

The triangle is stable and pressure-resistant. There are triangular figures in triangular frames, cranes, triangular booms, roofs, and steel bridges.

Simple pendulum

When playing on the swing, we may find that the swing swing is getting smaller and smaller, but the swing time for a week does not become shorter, and the time is always similar, why?

Because the swing is an approximate pendulum movement. A single pendulum is a small swing with a stall angle of less than 100, which is a device that can produce reciprocating swings, and the end of a thin rod or non-extendable thin rope is suspended at a certain point in the gravity field, and a heavy ball is consolidated at the other end, which constitutes a single pendulum.

Kinetic and potential energy

Mechanical energy is the sum of kinetic and potential energy.

Kinetic energy is the energy that an object has when it is in motion.

Potential energy includes gravitational potential energy and elastic potential energy. Gravitational potential energy is the energy produced by an object as a result of being lifted. Elastic potential energy is the energy produced by an object due to elastic deformation.

Energy conversion

Since mechanical energy is the sum of kinetic energy and potential energy, the transformation relationship between the two is: when the object falls, the smaller the height, the smaller its gravitational potential energy, but the speed of the object will be faster and faster, and the kinetic energy will be larger and larger. If air resistance is not taken into account, mechanical energy is constant, and the part of gravitational potential energy that decreases becomes kinetic energy.

Energy change during swing:

Height: Lowest point – > highest point – > lowest point

Speed: Maximum speed – > speed is zero – > speed is maximum

Energy: maximum kinetic energy – > maximum potential energy – maximum kinetic energy >

Reference model for swings

Mission expansion

Transform the single swing into a double swing

After-class exercises

1. Please list the use of triangle stability in life.

2. Which position is the highest single pendulum? Where is the fastest speed? Where is the potential energy greatest? Where is the kinetic energy greatest?

This section about the swing content is these, if you have any questions about the content of this lesson, as well as the “National Youth Robot Technology Level Examination”, welcome to send a message to the “Zhihui Brick” public account, the editor will reply to you in time!

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