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# NCERT Solutions for Class 9 Science Chapter 8 – Motion

NCERT Class 9 Science Solutions for Chapter 8 Motion by Instasolv introduces you to the concepts of Motion, distance, movement, velocity and speed. In this chapter of NCERT Solutions for Class 9, you will have an idea of the basics of physics and the physical forces which work around us. The chapter tackles the fundamentals and mechanics of these forces with their mathematical equations and their application in numerical problems.

CBSE Class 9 NCERT Science Chapter 8 Motion consists of 6 exercises and 30 questions in total. All of these questions aim at testing your analytical and observational skills with respect to the ideas introduced to you in the chapter. The chapter includes the equations of motions. There are also graphs of combinations of distance, velocity and time. Topics like acceleration, nature of graph curves and uniform and non-uniform acceleration. All these are very important topics that you must practice well for CBSE exams.

## Important Topics of NCERT Class 9 Science Solutions for Chapter 8 Motion

Speed

The NCERT Solutions class 9 science chapter 8 introduces you to the fundamental concepts of speed with reference to its formula and the role it has in the movement of a particle and its distance and time. In a given interval of time, the distance that is travelled by an object is termed as the speed of the object. Speed of an object has no direction. It is equal to the ratio of distance to time of the object body. Unlike some other physical forces, the speed of an object can never be a negative value, however, the speed of the object can be nil at any point.

Speed = Distance Travelled/Time taken

Velocity

In a given time period the displacement that occurs in an object’s position is known as its velocity. Velocity has a distinct direction. It is equal to the proportion of displacement of the object to the time interval in which the displacement was carried out. In case of the velocity of an object, it can be negative, positive or null.

Uniform and Non-Uniform Acceleration

Acceleration is the ratio of the difference between final and initial velocity to the time. It is of two kinds – uniform acceleration and non-uniform acceleration. If a body travels in the straight-line path such that the change in its velocity is uniform and therefore it is known as uniform acceleration. Opposite to this if a body travels in a straight line path with velocity increasing and decreasing in an unequal amount, the acceleration is termed as non-uniform acceleration.

Numerical Questions

The chapter deals largely with numerical problems which are based on the concepts that have been introduced in the chapter and the mathematical equations and formulas of the same.

Example

A train starting from a railway station and moving with uniform acceleration attains a speed of 40 km/h in 10 minutes find the acceleration of the train.

Solution

The initial velocity of the train = 0 (keeping in account the initial rest state of the train)

Final velocity of the train = 40 km/hr = 40 x 5/18 = 11.11 m/s

Time taken = 10 minutes = 600 s

Acceleration = 11.11 – 0 /600 = 0.0185 m/s square

### Exercise-wise discussion of NCERT Class 9 Solutions Chapter 8 Motion

1. Numerical problems and NCERT Science Class 9 Chapter 8 comprises of numerous questions of various kinds. These include short answer questions, diagram based questions, graph-based questions.
2. The theoretical questions in the chapter are less as compared to the numerical problems. You will have a good command on these mathematical and conceptual problems, once you fully engage with these questions and solutions.
3. The first exercise begins with an analytical and reasoning question. It requires you to have thorough knowledge about the fundamentals of displacement, motion and distance.
4. Further, the questions test your comparative skills. There are questions which require you to differentiate between terms like speed and velocity.
5. Then there are questions which require to the point answers. They are based on the various conditions of application of the physical quantities you have tackled in the chapter.
6. The chapter has a majority of numerical problems. These deal with the mathematical formula and equations that have been taught in the chapter. These problems require you to derive the speed, acceleration, time etc. based on the conditions that are given in the question.
7. Graphs have also been included in the questions. Their curves, shape, direction, etc. are to be noted, drawn or used to find out quantities in the solutions.

### About NCERT Class 9 Science Chapter 8 Solutions by Instasolv

• At Instasolv, you will find all the NCERT solutions for class 9 science chapter 8 compiled in an easy to access manner.
• These solutions adhere to the CBSE exam pattern for class 9.
• We have hired the best science experts and teachers from all across India who crafted these solutions for your benefit.
• Our solutions contain all the information that you require for this chapter.
• With the help of our NCERT solutions, you will be able to prepare for your exams easily.
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