TS 7th Class Science Important Questions 4th Lesson Motion and Time

These TS 7th Class Science Important Questions 4th Lesson Motion and Time will help the students to improve their time and approach.

TS 7th Class Science Important Questions 4th Lesson Motion and Time

Question 1.
Write the differences between uniform and non-uniform motion.
Answer:

Uniform motion	Non-Uniform motion
1. If a body covers equal distances in equal intervals of time, it is said to be in uniform motion. 2. Eg : A fan running at fixed speed.	1. If a body covers unequal distances in equal intervals of time, it is said to be in non-uniform motion. 2. Eg : Movement of housefly.

Question 2.
Classify different types of motions with examples.
Answer:
Based on the path taken by the bodies in motion, we classify motion of bodies as :

• Translatory motion Eg : Movement of car on a road
• Rotatory motion Eg : Movement of top
• Oscillatory motion Eg: Movement of swing

Question 3.
When is a body said to be in oscillatory motion?
Answer:
When a body is in ‘to’ and Tro’ motion along the same path, then the body is said to be in oscillatory motion.

Question 4.
Define motion. Explain the types of motion with examples.
Answer:
1. An object is said to be in motion if it changes its position with respect to its surroundings in a given time.
2. Based on the path taken by the bodies, motions are classified as

• Translatory motion
• Rotatory motion and
• Oscillatory motion.

i. Translatory motion : If all parts of a moving body move in the direction of motion, then the motion is said to be translatory motion. Eg : Moving car on the road, train on the track.

Translatory motion is further divided into two types. They are
a. Rectilinear motion and
b. Curvilinear motion.

a. Rectilinear motion : lf a body is in translatory motion, it moves along a straight line.
Then, motion is called rectilinear motion.
Eg: Movement of a train on tracks.
A mango falling from tree.

b. Curvilinear motion : If a body is in translatory motion, it moves along a curved path.
Then motion is called curvilinear motion.
Eg: Bus moving on hill station road.
Needle in a speedometer.
A spinning top.

ii. Rotatory motion : Motion of all particles of a moving body follow a circular path with respect to a fixed centre. Then motion is called rotatory motion.
Eg: Motion of blades of a ceiling fan.
Motion of earth around the sun.

iii. Oscillatory motion : The ‘to’ and ‘fro’ motion of an object about a fixed point always following the same paths is called oscillatory motion.
Eg : Pendulum of clock.
Motion of needle in a sewing machine.

Question 5.
Classify the following motions into translatory, rotatory and oscillatory motions?
a. walking man on the road
b. cradle
c. rotation of fan
d. motion of pendulum of clock
e. Rotation (spinning) of a top.
Answer:

a. walking man on the road	Translatory motion
b. cradle	Oscillatory motion
c. rotation of fan	Rotatory motion
d. motion of pendulum of clock	Oscillatory motion
e. Rotation (spinning) of a top.	Rotatory motion

Question 6.
A Garuda bus travels at a speed of 80 km/hour. How far will it travel in 8 hours?
Answer:
Speed of the bus = 80 km/hours
Travelled hours = 8 hours
Distance travelled = Speed X Travelled hours
= 8 x 80
= 640 km

Question 7.
A train travels at a speed of 120 km per hour. What is the time taken by it to travel 480 km?
Answer:
Speed of the train per hour 120 km
Distance travelled = 480 km
Time taken =

The time taken to travel 480 km = 4 hours.

Question 8.
How can you decide whether an object is moving faster or slower?
Answer:
The distance travelled by an object in a given interval of time can help us to decide which one is faster and which one is slower.

Question 9.
What are the units for measuring time.
Answer:
Second, minute, hour, week, fortnight, month, season, ayanam etc are units for measuring time.

Question 10.
How can you calculate average speed?
Answer:
Average speed of an object can he calculated by the formula,
\(\text { Average speed }=\frac{\text { Total distance travelled }}{\text { Total time taken to travel the distance }}\)

Question 11.
The speed of car is 72 km/h, convert its speed to rn/s.
Answer:
The speed of car = 72 km/h.

Question 12.
The speed of a car is 56 km/h, where as the speed of a bus is 20 m/s. Which vehicle moves faster?
Answer:
Speed of a car = 56 km/h
Speed ofa bus = 20 m/s

Question 13.
A. The speed of a bus is 72 km/h, where as the speed of a car is 12.5 m/s. Calculate which vehicle moves faster?
Answer:
The speed of the bus is expressed in km/h.
The speed of the car is expressed in rn/s. To compare both speeds one of them must be converted into another.
Speed of a bus = 72 km/h
Speed of a car = 12.5 m/s
1km/h = 5/18 m/s.
1 m/s = \(\frac{18}{5}\)km/s.
Thus, the speed of car is 12.5 x \(\frac{18}{5}\)km/h = 45 km/h.
Hence, the bus moves faster than the car.

B. Look at the following pictures. Identify the motions and give some more examples to the motions?


Answer:
Name of the motion:
Examples:

Translatory	Rotatory	Oscillatory
Moving Car	Rotating Fan	Sewing machine
Running on the road	Rotation of Earth	Pendulurn
Moving animals on the road.	Movement of pot	Swinging of girl

Question 14.
What would happen if we don’t find motion in every object?
Answer:
Lack of motion on the Earth causes many problems.

• Earth will stop revolving round the sun. As a result, time and function will “automatically stop”.
• Seasons will disappear on the planet. Therefore, life of living things will face serious problems.
• Absence of motion in the objects will lead to disappearance of works done by them.

Question 15.
What question you will ask about motion and its categories?
Answer:

• How are motions classified?
• What is the importance of knowing nìotwn and its classification.?
• What are uses of motion?
• Is there any relationship between motion and time?

Question 16.
What difference do you find in the movement of the hands of a clock and the body movements of a butterfly? In these two movements in which case is the change of position with time constant?
Answer:

• Hands of wall clock and the butterfly are in motion.
• They change their position with time.
• But the change of position with the time in clock is constant.
• Hands in the clock move regularly in clockwise direction.
• Movement of hands in butterfly is irregular.

Question 17.
Write the observations you made in the following objects regarding types of motion.
a. Spinning top
b. Working drill bit
c. Motion of cycle wheels.
Answer:
a. Spinning top : The top while spinning follows a circular path with respect to a fixed centre of axis of rotation. It exhibits rotatory motion.

b. Working drill bit : Electrical drill bit has sharp pointed screw. It spins very fast with electrical power. Pointed screen takes a fixed centre and pierces into the wall to make hole. It also exhibits rotatory motion.

c. Motion of cycle wheels: It was observed that moving cycle wheels exhibit both translatory and rotatory motion. Wheels change their point of place to another place in a specific direction. Hence, cycle wheels exhibit rectilinear motion.

Units of time
60 seconds	–  1 minute
60 minutes	–  1 hour
24 hours	– 1 day
365 days	– 1 year
10 years	– 1 decade
10 decades	– 1 century
10 centuries	– 1 millennium

a. How many seconds for 1 hour?
Answer: 3600 seconds br 1 hour.

b. How many years for 1 decade?
Answer: 10 years for 1 decade

c. How many decades for 1 cerutury?
Answer: 10 decades for 1 century

d. How many years for 1 millennium?
Answer: 1000 years for 1 millennnium

Question 19.
Read the table and answer the questions given below.

Time	Reading of distance covered
0 minutes	0 kilometres (0 km)
10 minutes	15 kilometres (5 km)
20 minutes	25 kilometres (25 km)
30 minutes	38 kilometres (38 km)
40 minutes	60 kilometres (60 km)

a. What is the total distance travelled by the car?
Answer: 60 kilometres

b. What is the time taken to travel the distance?
Answer: 40 minutes

c. How do you find the speed of a car?
Answer: Dividing the total distance travelled by the car by the total time taken to cover that distance.

d. At what time gap, the speed of the car was high?
Answer:  At the time gap between 30 and 40 minutes, the speed of the car was high.

Question 20.
Observe the following data and answer the questions.

Time	Readings of speedometer- distance travelled by a car
0 minutes	0 km
10 minutes	25 km
20 minutes	50 km
30 minutes	75 km

1. How do you find the speed of a car?
Answer: The speed of a car can be found by speedometer.

2. Is the speed of the car uniform throughout the journey?
Answer: No, the car is moving in non-uniform speed.

3. What is the total distance travelled by the car in 30 minutes?
Answer: The total distance travelled by the car in 30 minutes is 75 km.

Question 21.
Observe the following table and answer the questions.

Time in seconds	Distance travelled
0 minutes	Car – I	Car – II
	0 m	0 m
10 minutes	100 m	100 m
20 minutes	200 m	250 m
30 minutes	300 m	480 m

1. Which car moves in uniform motion?
Answer: Car – I.

2. Which car moves faster and which car moves slower?
Answer: Car – I slower, Car – II faster

3. Which car moves in non-uniform motion?
Answer: Car – II moves in a non-uniform motion

4. At 0 seconds, what is the state of Car I and Car II
Answer: Both the cars are at rest.

Question 22.
Read the given table and answer the question.

S.No.	Apparatus	Motion
1	Fan	Rotatory
2	Cradle	Oscillatory

a. In cradle …………….. motion takes place.
Answer: oscillatory motion

Question 23.
Observe the given pictures and write what type of motion they exhibit?

Answer:

• Moving swing shows oscillatory motion.
• Motion of a car shows both translatory motion and rotatory motion (in the wheels.)
• Needle in the clock shows rotatory motion.

Question 24.
Comment on the given picture of fan regarding rotatory motion.
Answer:
While the blade of a fan is moving, the points A,B and C on the blade move to A₁, B₁, C₁ first and then move to A₂, B₂ and C₂ position. Thus, when a fan is in motion, each point on the blade moves in a circular path around the centre of the fan which is fixed.

Question 25.
How do we get advantages through motion of objects. Write suitable examples.
Answer:

• Rotatory motion in clock and oscillatory motion in pendulum of clock help us to calculate the time.
• Rotatory motion in electrical drill bit makes the hole to fix the furniture.
• Translatory and rotatory motion in vehicles carry the people and goods from one place to other place.
• Oscillatory motion of needle in sewing machine helps in designing many garments.
• The important fact is rotation of earth around the sun that leads us to day and night and various seasons.
• Every motion on the earth sustains the life.

Choose the correct answer:

I. Conceptual Understanding 

Question 1.
Based on the path of the bodies, the types of motions are
A) translatory
B) rotatory
C) oscillatory
D) All
Answer:
D) All

Question 2.
In the following, which one is translatory motion?
A) Rotation of earth
B) Movement of car on a road
C) Movement of swing
D) None
Answer:
B) Movement of car on a road

Question 3.
Movement of billiard ball is. ( )
A) Rotatory motion
B) Rectilinear motion
C) Curvilinear motion
D) Translatory motion
Answer:
C) Curvilinear motion

Question 4.
The basic unit of time is …. (  )
A) second
B) minute
C) hour
D) year
Answer:
A) second

Question 5.
The instrument used to measure time is …. ( )
A) scale
B) common balance
C) clock
D) speedometer
Answer:
C) clock

Question 6.
The pendulum of wall clock makes …. type of motion. ( )
A) rotatory
B) oscillatory
C) translatory
D) both rotatory and oscillatory
Answer:
B) oscillatory

Question 7.
The unit of speed in S.I. System ( )
A) m/s
B) km/h
C) km/s
D) m/h
Answer:
A) m/s

Question 8.
In olden days. the instrument used to measure time ( )
A) Digital clock
B) Quartz watch
C) Sundial
D) Electronic watch
Answer:
C) Sundial

Question 9.
10 decades = ( )
A) 1 millennium
B) 1 century
C) I day
D) 1 year
Answer:
B) 1 century

Question 10.
1 km/h= …………. ( )

Answer:
A.

II. Asking Questions and Making Hypothesis

Question 11.
Pendulum: Oscillatory motion:: Spinning top ? ( )
A) Linear motion
B) Rectilinear motion
C) Translatory motion
D) Rotatory motion
Answer:
D) Rotatory motion

Question 12.
One of the following does not belong to oscillatory motion.
A) Pendulum clock
B) Ball on the ground
C) Swing
D) Needle in the sewing machine
Answer:
B) Ball on the ground

Question 13.
Find the odd one out ( )
A) Rotatory motion
B) Rectilinear motion
C) Curvilinear motion
D) Translatory motion
Answer:
A) Rotatory motion

Question 14.
Pick up the wrong sentence. ( )
A) Motion of the ball in pin board shows rectilinear and curvilinear rIIotioti
B) Movement of the bus on hill station road shows a curvilinear motion
C) Motion of coins on a carrom board shows oscillatory motion
D) Motion of a ceiling fan shows rotatory motion.
Answer:
C) Motion of coins on a carrom board shows oscillatory motion

III. Experimentation and Field investigation

Question 15.
What type of motion you observe in a giant wheel. ( )
A) Oscillatory
B) Rotatory
C) Translatory
D) B and C
Answer:
B) Rotatory

Question 16.
The speed of the train will be calculated through the following formula: ( )

Answer:
D.

IV. Information Skills and Projects

Question 17.
Read the para and answer the question.
If a body in translatory motion moves along a curved path, then the motion is called curvilinear motion. It is a type of ( )
A) rotatory motion
B) translatory motion
C) oscillatory motion
D) above all
Answer:
B) translatory motion

Question 18.
Read the table and answer the questions.

Objects in motion	slow	fast
i. Aeroplane		✓
ii. Auto rikshaw		✓
iii. Rickshaw	✓	✓

How can you decide whether the motion of a body is slow or fast?
A) Based on speed per hour
B) Based on weight per kilogram
C) With the help of speedometer
D) Based on the speed per minute
Answer:
A) Based on speed per hour

V. Communication through Drawing and Model Making

Question 19.
Name the given picture and write its use ( )

A) Water vessel that measures weight
B) Sand bowl that measures motion
C) Sand clock that measures time
D) Fluid vessel that detects speed
Answer:
C) Sand clock that measures time

Question 20.
The moving bird in the picture shows ( )

A) uniform motion
B) rectilinear motion
C) oscillatory motion
D) non – uniform motion
Answer:
D) non – uniform motion

VI. Application to Daily Life and Concern to Bio Diversity

Question 21.
Rotatory and translatory motion helps us ( )
A) to know the time
B) in pedalling cycle easily
C) in hitting the coins on the carrorn board
D) to and fro action of an object
Answer:
B) in pedalling cycle easily

Question 22.
Good example for rotatory motion. ( )
A) The earth revolves around the sun
B) The sun revolves around the earth
C) Moving car on the road
D) Motion of a train on the track.
Answer:
A) The earth revolves around the sun