Std 6 th Science- 9. Motion and Types of Motion

Question 1:

Identify the types of motion.

(a) Movement of the earth around the sun : .......... .

(b) Movement of a ceiling fan : ..........

(d) A rocket launched from the ground : ..........

(e) A fish swimming in water : ..........

(f) The plucked string of a sitar : .......

Answer 1:

(a) Movement of the earth around the sun : Circular and periodic motion.

(b) Movement of a ceiling fan : Circular motion.

(d) A rocket launched from the ground : Non-uniform linear motion.

(e) A fish swimming in water : Random motion.

(f) The plucked string of a sitar : Oscillatory motion

Question 2:

Fill in the blanks.

(a) If a ball is released from the terrace of a building, it comes down in ........... motion. On the other hand, it reaches the ground in ........... motion if it is thrown with force away from the terrace in a direction parallel to the terrace.

(b) The motion of an aeroplane on the runway before take-off is.......... .

(d) Children sitting in a rotating giant wheel have ........... motion, while those sitting in a merry-go-round have a ........... motion.

(Linear, non-linear, circular, uniform linear, non-uniform linear, uniform circular, non-uniform circular, random)

Answer 2:

(a) If a ball is released from the terrace of a building, it comes down in non-uniform linear motion. On the other hand, it reaches the ground in non-linear motion if it is thrown with force away from the terrace in a direction parallel to the terrace.

(b) The motion of an aeroplane on the runway before take-off is non-uniform linear motion .

(d) Children sitting in a rotating giant wheel have non-uniform circular motion, while those sitting in a merry-go-round have a uniform circular motion.

Question 3:

How are we different?

(a) Oscillatory motion and linear motion.

(b) Linear motion and random motion.

Answer 3:

(a)

Oscillatory motion	Linear motion
The type of motion in which the object moves to and fro repeatedly about a mean or a fixed position is known as oscillatory motion.	The type of motion in which the object moves from one point to another in a straight line is called linear motion.
For example: Movement of the pendulum of a clock	For example: Vehicles moving on a straight road

(b)

Linear motion	Random motion
The type of motion in which the object moves from one point to another in a straight line is called linear motion.	The type of motion in which the direction of motion and the speed of an object changes continuously is called random motion.
For example: Vehicles moving on a straight road	For example: Children playing in a garden

(c)

Random motion	Oscillatory motion
The type of motion in which the direction of motion and the speed of an object changes continuously is called random motion.	The type of motion in which the object moves to and fro repeatedly about a mean or a fixed position is known as oscillatory motion.
For example: Children playing in a garden	For example: Movement of the pendulum of a clock

Question 4:

Explain in your own words, giving one example each.

(a) Linear motion

(b) Oscillatory motion

(d) Random motion

(e) Periodic motion

Answer 4:

(a) Linear motion: An object is said to have linear motion if it moves from one point to another in a straight line. For example: The motion of a moving car on a straight road.

(b) Oscillatory motion: The type of motion in which the object moves to and fro repeatedly about a mean or a fixed position is known as oscillatory motion. For example: The movement of pendulum of a clock.

(c) Circular motion: An object is said to possess circular motion if it moves from one point to another in such a way that its distance from a fixed point always remains constant. For example: The movement of the blades of a fan.

(d) Random motion: The type of motion in which the direction of motion and the speed of an object changes continuously is called random motion. For example: Children playing in a garden.

(e) Periodic motion: An object is said to possess periodic motion if it moves in such a way that it repeats its motion after a certain interval of time. For example: The motion of a swing.

Question 5:

Answer the following questions in your own words.

(a) Which types of motion are seen in birds flying in the sky ?

(b) Write in detail about your experience of various types of motion while riding a bicycle on a road.

Answer 5:

(a) Birds flying in the sky have random motion as their direction of motion and speed continuously changes.

(b) While riding a bicycle on a road, following types of motion can be seen:

The wheels of the bicycle are in uniform or non-uniform circular.
The legs of the person riding the bicycle are in uniform or non-uniform circular motion.
The bicycle is in uniform or non-uniform linear motion. It can also be in non-uniform motion.