Motion Class 9 CBSE Notes - Chapter 8

The world that we see around us is in constant motion – this is due to the fact that the earth itself is in motion, orbiting the sun at a speed of over 107,000 km/h. But exactly is motion and how do we define it?

Describing Motion

If a body is constantly changing its position with respect to time or point of reference, then, that body is said to be in motion. There are various types of motion, namely:

  1. Uniform Motion

It occurs when equal distances are covered in equal intervals of time by a body. Light travels in uniform motion through a vacuum.

  1. Non-uniform motion

Unlike uniform motion, a body travels unequal distances in equal intervals of time. A car moving through traffic constitutes non-uniform motion.

  1. Periodic motion

This is essentially a type of motion that repeats itself at periodic intervals of time. A vibrating tuning fork is an example of periodic motion

  1. Oscillatory motion

This is a form of periodic motion that occurs in a regular cycle. A sine wave, the swing of a pendulum are examples of oscillatory motion.

Motion class 9 also explains the concept of motion along a straight line, one of the most simple types of motion. It is also called linear motion or rectilinear motion.

Motion Class 9 Notes – Questions

  1. What do you understand by the term “motion?”
  2. Explain Uniform Motion
  3. What is the difference between Uniform and Non-Uniform Motion?
  4. What is meant by the rate of change of velocity?
  5. Give 3 examples of circular motion.

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Further Reading:-

Practise This Question

With respect to the following statements, choose the correct answer.
i.Food security depends on both, the availability of food and access to it.
ii.Mixed farming degrades the nutrient quality of the soil.
iii.Fertilisers are commercially produced plant nutrients.