Motion | CBSE Class 9 Science | Future Classes
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Unlock the Secrets of Motion with Future Classes' CBSE Class 9 Science Course

The CBSE Class 9 Science notes on Motion offer a comprehensive overview of the concepts, theories and topics related to this subject. Students can learn about the different types of motion, including linear and circular, and understand the factors that affect motion, such as force, mass, speed and acceleration. They can also explore the laws of motion, including Newton's three laws, and learn about the different types of energy, such as the kinetic and potential energy. With the help of these notes, students can gain a better understanding of the concepts of motion and be better equipped to solve problems related to it.

At Future Classes, we are dedicated to helping students achieve academic success. That's why we offer a variety of study resources, including our short notes on CBSE class 9 science chapter motion. Written by Anurag, our notes are easy to read and provide a comprehensive overview of the subject. Download your copy today and start studying smarter!

MOTION

Rest:

​A body is said to be in a state of rest when its position does not change with respect to a reference point.

Motion:

A body is said to be in a state of motion when its position change continuously with reference to a point.

Scalar quantity:

It is the physical quantity having magnitude but no direction. Example -distance, speed.

Vector quantity:

It is the physical quantity having both magnitude and direction. Example - displacement, velocity.

Unit system

  1. M.K.S. system (S.I. system) – meter, kilogram, second

  2. C.G.S. system – centimeter, gram, second

  • S.I. system – International system of unit

Distance

The actual path of length traveled by an object during its journey from its initial position to its final position is called the distance.

  • Distance is a scalar quantity.

  • It remains positive, can’t be zero or negative.

Displacement

The shortest length between the initial point and far point of an object.

  • It is a vector quantity.

  • It can be positive (+ve), negative (-ve), or zero.

distance and displacement

Uniform Motion:

When a body travels an equal distance in an equal interval of time, then the motion is said to be uniform motion.

Non-uniform Motion:

In this type of motion, the body will travel unequal distances in equal intervals of time.

Speed:

The distance traveled by a body per unit of time is called speed.

speed formula

  • SI unit is m/s (meter/second)

  • For non-uniform motion

average speed formula

Velocity:

It is the speed of a body in a given direction.

velocity formula

SI unit of velocity is m/s

Velocity is a vector quantity.

  • For non-uniform motion

average velocity formula

  • For uniformly changing velocity

avg velocity formula

Acceleration:

Acceleration is seen in non-uniform motion and it can be defined as the rate of change of velocity with time.

acceleration formula

Where, v = final velocity, u = initial velocity

S I unit is meter/second2

Retardation/Deceleration

Deceleration is seen in non-uniform motion during a decrease in velocity with time. It has the same definition as acceleration. (-a)

Graphical Representation of motion

Distance-time graph of an object moving with uniform speed

distance time graph for uniform speed

Distance-time graph for a car moving with non-uniform speed

distance time graph for non uniform motion

Velocity-time graph for uniform motion of a car

velocity time graph for uniform motion

Velocity-time graph for a car moving with uniform accelerations.

velocity time graph for uniform acceleration

Velocity-time graphs of an object in nonuniformly accelerated motion.

velocity time graph for non uniform accelerated motion

Equation of Motion (For Uniformly Accelerated Motion)

about equation of motion

Graphical Derivation:

First Equation

Suppose a body has initial velocity ‘u’ (i.e., velocity at time t = 0 sec.) at point ‘A’, and this velocity changes to ‘v’ at point ‘B’ in ‘t’ sec. i.e., final velocity will be ‘v’.

velocity time graph for uniform motion
proof of first equation of motion

Second Equation

proof of second equation of motion

Third Equation

proof of third equation of motion

Uniform Circular Motion

In such a motion the speed may be the same throughout the motion but its velocity (which is tangential) is different at every point of its motion. Thus, uniform circular motion is an accelerated motion.

uniform circular motion digram

  • Some units

some units

Our website offers a variety of PDF downloads for CBSE Class 9 Science students. Our resources cover important topics such as Motion, allowing students to gain a deeper understanding of the subject. Our PDFs are easy to download and provide a great resource for students to use for their studies. Our materials are designed to help students develop their knowledge and skills in the areas of Science and Motion. We also offer support to help ensure that students are able to understand and apply the concepts they have learned. Our PDF downloads are a great way for students to stay ahead in their studies and succeed in their CBSE Class 9 Science course.

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Motion - Chapter 7, CBSE Class 9

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