12. Motion and Types of Motion
Complete solutions to the Exercises, with a classification chart of the types of motion and worked reasoning for every situation. Maharashtra State Board (Balbharati), Grade Six General Science.
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About the chapter
When the position of an object changes, we say it is in motion. This chapter tells us how to decide whether an object is moving. It also explains the different types of motion.
Key points
- Motion is decided with respect to a reference point.
- In linear motion, an object moves in a straight line.
- Non-linear motion can be circular, oscillatory or random.
- An object can show more than one type of motion at the same time.
- Every object on the earth is in motion, because the earth itself moves.
Words to remember
- motion – change in the position of an object
- rest – no change in the position of an object
- reference point – a fixed point used to decide motion
- oscillatory motion – moving to and fro about a point
- random motion – motion with no fixed direction
Exercises
Types of motion.
Linear motion: (1) A meteor falling from the sky, (3) A rocket launched into the sky, (5) A friend sliding down a slide
Non-linear motion: (2) A snake slithering on the ground, (4) Children running in kho-kho, (6) An athlete jumping high after a short run
(1) An object going in a straight line is in oscillatory motion.
False. An object going in a straight line is in linear motion.
(2) All the parts of a bicycle going along the road undergo linear motion.
False. The wheels and pedals of a bicycle move in circular motion.
(3) The motion of a giant wheel at a fair is linear.
False. The motion of a giant wheel is circular.
(4) At the circus, a swinging act was performed at a height. In the end, the performers released the swing and jumped down onto the safety net below. In this entire act, the motion of performers is an oscillatory motion.
False. The motion is oscillatory while swinging and linear while jumping down.
(5) When a drilling machine starts drilling a hole in wood or a wall, both linear and circular motions can be observed.
True.
(1) When do we say that an object is in motion?
When the position of an object changes with respect to a reference point, it is in motion.
(2) What is the main difference between linear and nonlinear motion?
In linear motion an object moves in a straight line, but in non-linear motion it does not.
(3) What is the motion of a child, sitting on a horse running on a straight road?
The child is in linear motion.
(4) Which type of motion causes diaphragm of a drum to produce sound?
Oscillatory motion of the drum’s diaphragm produces sound.
(1) A boy is walking fast in a straight line, his hands are moving back and forth.
Boy – linear motion; hands – oscillatory motion.
(2) A girl is rotating her arms from the shoulder.
Circular motion.
(3) A boy is jumping high.
Linear motion.
(4) The motion of a girl skipping and her rope.
Girl – linear motion; rope – circular motion.
- Linear motion – when it flies straight ahead.
- Oscillatory motion – of its wings moving up and down.
- Circular motion – when it flies round and round in the sky.
- Random motion – when it changes direction suddenly.
Tyre: Circular motion (spinning) and linear motion (moving forward).
Girl: Linear motion (running forward) and oscillatory motion of her hands and legs.
Yes, it is true.
- The earth rotates on its axis and revolves around the sun.
- All objects on the earth move along with it.
- So every object on the earth is in motion.
- Blades – circular motion
- Motor shaft – circular motion
- Head of a table fan (turning left and right) – oscillatory motion
- Stand and base – at rest