# Motion Class 9 Notes

Greetings to all, Here We have provided summary and revision notes for Class 9 Science Chapter 8. This CBSE note contains CBSE Key Notes, CBSE Revision Notes, Short Key Notes, diagrams of the complete Chapter 8 titled Motion of Science taught in class 9. If you are a student of class 9 who is using the NCERT Textbook to study Science, then you must come across Chapter 8 Motion. After you have studied the lesson, you must be looking for notes to memorize. Here you can get complete Chapter 8 Motion Class 9 notes in one place. For a better understanding of this chapter, you should also see NCERT Solutions for Class 9 Science Chapter 8 Motion.
CBSE Class 9 Science Notes Chapter 8 Motion Pdf free download is part of Class 9 Science Notes for Quick Revision. Here we have given NCERT Class 9 Science Notes Chapter 8 Motion.

### Detailed Table of the Chapter 8 Notes –  Motion Class 9 Notes PDF

 1 Board CBSE 2 Textbook NCERT 3 Class Class 9 4 Subject Science Notes 5 Chapter Physics chapter 8 6 Chapter Name Motion 7 Category CBSE Revision Notes

## Motion Class 9 Notes PDF

Introduction:

• One of the most common phenomena in the physical world in motion. Mechanics is the branch of physics that deals with the behavior of moving objects.
• Mechanics is divided further into two sections: Kinematics and Dynamics.
• Kinematics is the study of motion without regard for the cause of motion.
• Dynamics is concerned with the source of motion, which is force.

Motion and Rest:

• An object is said to be in motion if its position in relation to its surroundings changes in a given time.
• An object is said to be at rest if its position in relation to its surroundings does not change.
• A frame of reference is another object or scene against which we compare the position of an object.

Types of Motion:
There are three types of motion:

• Translatory motion
• Rotatory motion
• Vibratory motion

Translatory Motion:

• A particle in translatory motion moves from one point in space to another. This movement may be in a straight line or in a curved path.
• Rectilinear motion is defined as motion along a straight line.
• Curvilinear motion is defined as movement along a curved path.
• As an example, consider a car driving down a straight road.

Curvilinear Motion:
Rotatory Motion:
The particles of the body describe concentric circles around the axis of motion is rotatory motion.
Vibrational Motion:
Particles in vibratory motion move back and forth around a fixed point.
Distance and Displacement:
The distance between termini A and B is 150 kilometers. A bus connects Terminus A and Terminus B. The bus travels a distance of 150 kilometers. The bus returns from terminus B to terminus A along the same route. As a result, the total distance traveled by the bus from A to B and then from B to A is 150 km + 150 km = 300 km.
A bus traveling from point A to point B and back again.

• The distance traveled by a moving object is the length of the path the object takes.
• The measure of distance is a scalar quantity. The meter is the SI unit of distance.
• The bus’s position changed when it moved from Terminus A to Terminus B. The distance between A and B is 150 kilometers. The distance traveled on the return trip is also 150 kilometers.
• Displacement is the shortest path covered by a moving object in a specified direction from the point of reference (the initial position of the body).

Note:

• However, the displacement when the bus moves from A B to B B is zero. The meter is the SI unit of displacement.
• Displacement is a vector, which means that it is represented by a number with appropriate units and directions.
• To emphasize the distinction between displacement and distance, consider a few more examples.

Assume a person moves 3 meters from point A to point B and 4 meters from point B to point C, as shown in the figure. He has traveled a total distance of 7 meters. But is he really 7 meters away from his starting point? No, he is only 5 meters away from his initial position, implying that he is displaced by the shortest distance between his initial and final positions.
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