The DAV Class 6 Science Solutions and DAV Class 6 Science Chapter 6 Question Answer – Measurement and Motion are essential study tools for DAV public school students in Class 6.
DAV Class 6 Science Ch 6 Question Answer – Measurement and Motion
DAV Class 6 Science Ch 6 Solutions – Measurement and Motion
Something To Know
A. Fill in the blanks.
Question 1.
The standard unit of mass is the ______
Answer:
Gram
Question 2.
While sitting in a moving bus, we are in ______ with respect to the surroundings.
Answer:
motion
Question 3.
A moving car, going on a narrow straight road, is having a (nearly) ______ motion.
Answer:
rectilinear
Question 4.
The motion, of the needle of a sewing machine is an example of an ______
Answer:
oscillatory motion
Question 5.
The motion of the earth, around the sun, is ______ in nature.
Answer:
periodic
B. Write True or False for the following statements.
1. Measurement is needed to make correct decisions.
2. A metre scale can be used for measuring the length of a playground.
3. The motion of the moon, around the earth is a rectilinear motion.
4. The motion, of the pedal of a bicycle, is a circular motion.
5. The motion, of a giant wheel, is a rotatory motion.
6. When we draw water from a well, we are pushing at the rope.
Answer:
1. Measurement is needed to make correct decisions. (True)
2. A metre scale can be used for measuring the length of a playground. (False)
3. The motion of the moon, around the earth is a rectilinear motion. (False)
4. The motion, of the pedal of a bicycle, is a circular motion. (True)
5. The motion, of a giant wheel, is a rotatory motion. (True)
6. When we draw water from a well, we are pushing at the rope. (False)
C. Tick (✓) the correct option.
1. The standard unit of length is the
(a) metre
(b) millimetre
(c) kilometre
(d) centimetre
Answer:
(a) metre
2. The standard unit of time is the
(a) Second
(b) Day
(c) Year
(d) Minute
Answer:
(a) Second
3. The motion, of a tip of pen, while writing, is a/an
(a) Rectilinear motion
(b) Oscillatory motion
(c) Curvilinear motion
(d) Rotatory motion
Answer:
(c) Curvilinear motion
4. Which of the following four ‘motions’ is different from the other three?
(a) The moving blades of a fan
(b) A spinning top
(c) A potter’s wheel
(d) A fruit falling from a tree
Answer:
(d) A fruit falling from a tree
5. The motion of a swinging pendulum is a/an
(a) Curvilinear motion
(b) Rotatory motion
(c) Oscillatory motion
(d) Rectilinear motion
Answer:
(c) Oscillatory motion
D. Answer the following questions in brief.
Question 1.
How does measurement help us in our day-to-day life?
Answer:
Measurement is very important for our day-to-day life. Let us take example of a piece of cloth being bought for a dress. You need to know the exact length of cloth which needs to be bought. The cloth merchant uses a metre scale to measure the length of the cloth. If he would give a cloth piece on the basis of estimation, the cloth could be either less or more than what is required. If the cloth piece is less than what is needed, then it won’t be possible to make the dress. On the other hand, if the cloth piece is more than what is needed, it would result in wastage of cloth.
Question 2.
Which type of watch is used to measure time intervals in a ‘200 metre race’?
Answer:
Stop watch is used to measure time intervals in a car race.
Question 3.
When do we consider an object to be in motion?
Answer:
When the position of an object changes with change in time, the object is considered to be in motion.
Question 4.
Name three different types of motions and give one example of each.
Answer:
Three different types of motions are as follows:
(a) Rectilinear motion – car on straight road
(d) Curvilinear motion – car on a bend
(c) Rotatory motion of wheel
Question 5.
State the difference between ‘periodic’ and ‘non-periodic’ motion.
Periodic motion
The motion repeats after certain time interval.
Example’, motion of a pendulum
Non-periodic motion
The motion is not repeated.
Example’, Motion of a train
E. Answer the following questions.
Question 1.
Why does a measurement need both a ‘number’ and a ‘unit’ for its complete specification?
Answer:
We know that measurement is the process of comparing an unknown quantity with a known quantity where the known quantity is called the unit. While measuring some physical quantity with a unit we need to express the number of times that physical quantity is in terms of that unit. ‘Number of times’ and unit give the complete specification of a measurement. Let us take example of measure of your height. If someone says that your height is 140 then it does not specify whether it is 140 cm or 140 m or 140 inches. Similarly, if someone says that your height is in inches then it doesn’t specify the number of inches. On the other hand, if someone says that your height is 140 inches, then everything becomes clear.
Question 2.
Why is a foot step, or a hand span, not used as a standard unit of length?
Answer:
Foot step or a hand span can be of different lengths in different people. If two people measure a particular length with their hand span, both of them would come with different numbers to express the measurement. It is clear that foot step or hand span can never be the same for all and hence cannot be used as standard unit for measuring the length.
Question 3.
Radha was performing an experiment in the Science Laboratory. The metre scale, that she was using to measure the length of the string, was worn out between its 1 cm and its 2 cm marks, due to overuse.
(a) She measures the length of a string by keeping its one end at the 3.0 cm mark. If the other end of the string reads 92.8 cm, find the length of the string.
Answer:
Length = Final reading – Initial reading = 92.8 – 3 = 89.8 cm
(b) Write the precautions, to be followed, when a meter scale is being used for measuring a given length.
Answer:
The following precautions need to be followed when a metre scale is being used for measuring a given length:
- The scale should be placed in such a way that its edge is along and parallel to the length which is being measured.
- The zero mark of the scale should coincide with one end of the length to be measured.
- The position of eye should be vertically above the point and in line with the reading to be taken. Change of the eye position would give wrong reading.
- Worn-out or broken scale should not be used.
Question 4.
Explain the difference between ‘rest’ and ‘motion’. Give two examples of each.
Answer:
When an object is in rest then its position does not change with change in time. On the other hand, when an object is in motion, then its position changes with change in time. A book on the bookshelf, a stone on pavement, etc. are examples of objects in rest. A moving car and a moving train are examples of objects in motion.
Question 5.
Distinguish between:
(a) Rectilinear and curvilinear motion
(b) Rotation and revolution
Give one example of each from our daily life.
Answer:
When an object is moving on a straight path, it is said to be in rectilinear motion, for example, a fruit falling from a tree. When an object is moving along a curved path, it is said to be in curvilinear motion, e.g. a car moving on a bend. When an object moves around its axis, its motion is called rotation, e.g. a spinning top. When an object moves on a circular path, its motion is called revolution, e.g. movement of earth around the sun.
Question 6.
Define the following types of motion. Give one example of each of these two types of motion.
(a) Rectilinear motion
Answer:
When an object is moving on a straight path, it is said to be in rectilinear motion, for example, a fruit falling from a tree and a bullet fired from a gun are in rectilinear motion.
(b) Circular motion
Answer:
When an object is moving along a curved path, it is said to be in curvilinear or circular motion, e.g. a car moving on a bend and a horse running on a circular track are showing circular motion.
Value Based Questions
When Kami’s mother saw her school calendar, she noticed that the annual sports day was still four months away. She, however, advised Kami to follow a regular, systematic practice schedule, right from the start. Kami followed her advice and did not deviate at all from her regular practice. On the sports day, she won the first prize in her event. Her mother told her that she succeeded in her efforts because she did her practice in a way similar to that of an object having a rectilinear motion.
Question 1.
Why did Kami’s mother compare her practice schedule with that of an object having a rectilinear motion?
Answer:
In rectilinear motion, the object never deviates from its set path. Kami did not deviate from her chosen practice schedule. Hence, her mother compared her practice schedule with that of an object having a rectilinear motion.
Question 2.
State the values displayed by Kami.
Answer:
Discipline, determination
Question 3.
Play a game in which each participant picks up one (folded) paper chit, from a collection, having names of different types of motion written on them. The participant then has to speak of a ‘daily life situation’ that can be co-related with the type of motion written on her/ his paper chit.
Answer:
Do it yourself.
Something To Do
Question 1.
Create your own amusement park!
- Visit an amusement park with your family, or teachers. Look closely at each ‘ride’, and identify its types of motion.
- Take a pitcure, or use a drawing, of each of the available ‘rides’, and label their type of motion.
- With the drawings/pictures of rides, set up your ‘amusement park’, on a chart paper, or a cardboard. Also draw some roads, grass, sidewalks, and other things, you find at an amusement park.
- After your amusement park has been set up, take your friends, or parents, on a ‘tour’ of it. Tell them about each ‘ride’ and the types of motion associated with that ride.
Answer:
Do it yourself.
Question 2.
Take pictures of different objects, having different types of motion. Label the type/types of motion in each case and make a collage titled “A Moment of Movement”. The picture may be taken from old magazines/newspaper/books, etc.
Answer:
Do it yourself.
Question 3.
Identify different types of motion from the ‘Word Puzzle’ given below. ‘Circular’ motion has been identified as an example for you.
Answer:
DAV Class 6 Science Chapter 6 Solutions – Measurement and Motion
I. Fill in the blanks.
Question 1.
A ______ quantity is a measurable quantity.
Answer:
Physical
Question 2.
______ and ______ give complete picture of measurement.
Answer:
Number, unit
Question 3.
Foot span is not a ______ unit.
Answer:
Standard
Question 4.
The SI unit of mass is ______
Answer:
kilogram
Question 5.
The SI unit of length is ______
Answer:
Metre
Question 6.
A ______ is the most common tool for measuring length.
Answer:
Metre scale
Question 7.
The girth of a tree can be measured by ______ measurement.
Answer:
Indirect
Question 8.
A stone tied to a rope shows ______ motion.
Answer:
Circular
Question 9.
The motion of moon on its axis is an example of ______ motion.
Answer:
Rotatory
Question 10.
The pendulum of a clock shows ______ motion.
Answer:
Oscillatory
II. Tick (✓) the correct answer.
1. Which of the following is not a unit of time?
(a) Second
(b) Day
(c) Year
(d) Cubit
Answer:
(d) Cubit
2. Which of these is ideal for measuring the time taken by Usain Bolt to finish a 100 m sprint?
(a) Sand clock
(b) Digital clock
(c) Stop watch
(d) Pendulum clock
Answer:
(c) Stop watch
3. Which type of motion is shown by the wheels of a moving car?
(a) Rectilinear’ motion
(b) Curvilinear motion
(c) Rotatory motion
(d) Circular motion
Answer:
(c) Rotatory motion
4. What is the value of 54 km in terms of SI unit of length?
(a) 54 km
(b) 54000 m
(c) 5400000 cm
(d) 54000000 mm
Answer:
(b) 54000 m
5. How many seconds are there in a day?
(a) 24 x 3600 s
(b) 12 x 3600 s
(c) 6 x 3600 s
(d) 3600 s
Answer:
(a) 24 x 3600 s
6. All the clocks work on the principle of which of these?
(a) Rectilinear motion
(b) Rotatory motion
(c) Circular motion
(d) Oscillatory motion
Answer:
(d) Oscillatory motion
7. Which of these is in rest?
(a) A bird on a tree
(b) An apple on a tree
(c) The tree
(d) All of these
Answer:
(d) All of these
8. Which of these shows oscillatory motion?
(a) A train moving on a curved track
(b) A child on a swing
(c) A merry-go-round
(d) A ferry – wheel
Answer:
(b) A child on a swing
III. Answer these questions.
Question 1.
What do you understand by physical quantities?
Answer:
Measurable quantities are called physical quantities.
Question 2.
Define measurement.
Answer:
Measurement is a process of comparison of an unknown quantity with some known fixed quantity.
Question 3.
What is SI unit?
Answer:
SI unit is a system of internationally accepted and agreed units of various physical quantities.
Question 4.
Which are the three basic physical quantities?
Answer:
The three basic physical quantities are: length, time and mass.
Question 5.
What do you understand by indirect measurement?
Answer:
Sometimes, the object to be measured is first measured with a reference material. The reference material, in turn, is measured directly to arrive at the result. This process of measurement is called indirect measurement.
Question 6.
What is a stop watch? Give one example of its use.
Answer:
It is a special watch which can be started and stopped as per need. This is used for measuring the time for short duration activities, like running.
Question 7.
Define motion.
Answer:
If an object changes its position with respect to its immediate surrounding, it is said to be in motion. In other words, the change of position of an object, with change in time is called motion.
Question 8.
What is the difference and similarity between rotatory motion and circular motion?
Answer:
In both rotatory motion and circular motion, the object moves around a fixed axis. While
the position of the object does not change in case of rotatory motion, the position changes in case of circular motion.
IV. Projects
Question 1.
Make a list of 10 objects from your household which show rotatory motion.
Answer:
Do it yourself.
Question 2.
Make a list of 10 objects from your surroundings which show circular motion.
Answer:
Do it yourself.