"How to describe motion" Motion and force PPT courseware 2

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"How to describe motion" Motion and force PPT courseware 2

1. What is motion and stillness?

1. Mechanical movement

When students ride bicycles, the positions of people and bicycles relative to the ground are constantly changing; when a train is running on the rails, its position relative to the ground is constantly changing; when an airplane flies in the sky, its position relative to the ground is also constantly changing. …

In physics, the change of the position of one object relative to another object is called mechanical motion; referred to as motion.

How to determine whether an object is moving?

Compare Figure 7-1 (a) and (b), please help the little girl find it. Children No. ___ and No. ___ moved, while children No. ___ and No. ____ remained motionless.

2. Reference object: To determine whether an object is moving, you must first select an object as a reference. This object is called a reference object.

An object is said to be in motion when its position relative to a reference object changes;

If the object does not change its position relative to the reference object, it is said to be at rest.

2. Movement and stillness are relative

In this picture, are the people in the sightseeing elevator stationary or moving?

Using the ground as a reference, people are in motion;

Taking the elevator as a reference object, people are stationary.

Using the window as a reference, people are still.

It can be seen that whether an object is moving or stationary depends on the reference object chosen.

Depending on the reference object, the conclusions drawn may be different (it may be moving or stationary).

Movement and stillness are relative.

Example: Students are sitting in the classroom, taking the classroom as a reference object, you are ______, using the sun as a reference object, you are ______; using the bird flying by the window as a reference object, you are _ _____of;

Summary: Stillness is relative, motion is absolute.

Tell me: What other sports do you know?

Movement is a common phenomenon in nature. There are various forms of movement, and mechanical movement is only the simplest one.

Summarize

mechanical movement

Reference object

The relativity of motion and rest

Diversity of movement in nature

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"How to describe motion" Motion and force PPT courseware:

"How to describe motion" Motion and force PPT courseware teaching objectives 1. Know what mechanical motion is 2. Know that to judge whether an object is moving, you must first select a reference object, and be able to scientifically describe the motion and stillness of an object based on the reference object 3. Understand the existence of nature With various...

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Update Time: 2024-11-19

This template belongs to Physics courseware Guangdong and Shanghai version of eighth grade physics volume 2 industry PPT template

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