Measurement of Length and Motion Class 6 Questions and Answers NCERT Solutions
Class 6 Science Chapter 5 Measurement of Length and Motion Question Answer
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Question 1.
Some lengths are given in Column I of the table given below. Some units are given in Column II. Match the lengths with the units suitable for measuring those lengths.
Answer:
Distance between Delhi and Lucknow – kilometre
Thickness of a coin – millimetre
Length of an eraser – centimetre
Length of school ground – metre
Question 2.
Read the following statements and mark True (T) or False (F) against each.
(i) The motion of a car moving on a straight road is an example of linear motion.
Answer:
True
(ii) Any object which is changing its position with respect to a reference point with time is said to be in motion.
Answer:
True
(iii) 1 km=100 cm
Answer:
False
Question 3.
Which of the following is not a standard unit of measuring length?
(i) Millimetre
(ii) Centimetre
(iii) Kilometre
(iv) Hand-span
Ans.
(iv) Hand-span
Question 4.
Search for the different scales or measuring tapes at your home and school. Find out the smallest value that can be measured using each of these scales. Record your observations in a tabular form.
Answer:
Observations of different scales or measuring tapes are given below.
| Different scales or measuring tapes | Smallest value measured |
| 1. A plastic scale from pencil box | 1 mm |
| 2. A steel ruler | 1 mm |
| 3. Tailor’s measuring tape | 1 mm |
| 4. Steel measuring tape | 1 m |
Question 5.
Suppose the distance between your school and home is 1.5 km . Express it in metres.
Answer:
1 km = 1000 m
1.5 km = 1.5 × 1000 = 1500 m
Question 6.
Take a tumbler or a bottle. Measure the length of the curved part of the base of tumbler or bottle and record it.
Answer:
Measuring curved part of Tumbler/Bottle
Method 1 Take a tailor’s measuring tape to measure the length of the curved part of the base of tumbler or bottle.
Method 2 Run a thread along the curved part of the base of tumbler or bottle. And the length of the thread used can be further measured from a scale.
Question 7.
Measure the height of your friend and express it in (i) metres (ii) centimetres and (iii) millimetres.
Answer:
Assume your friend’s height is 4.5 feet.
(i) 4.5 feet =4.5 × 0.3=1.35 m (since, 1 feet =0.3 m)
(ii) 1.35 m=1.35 × 100=135 cm (since, 1 m=100 cm)
(iii) 135 cm=135 × 10=1350 mm (since, 1 cm=10 mm)
Question 8.
You are given a coin. Estimate how many coins are required to be placed one after the other lengthwise, without leaving any gap between them, to cover the whoie length of the chosen side of a notebook. Verify your estimate by measuring the same side of the notebook and the size of the coin using a 15 cm scaie.
Answer:
Take a notebook and place the coins one after the other lengthwise. The number of coins that you get by experimenting should be equal to the number of coins that can be calculated hy the method given below: Let’s say, the length of a notebook measured by 15 cm scale =20 cm or 200 mm and the height of one coin =2 mm (meastrements can vary).
No. of coins = Length of the notebook/ Height of one coin =200 mm / 2 mm=100 coins.
Question 9.
Give two examples each for linear, circular and oscillatory motion.
Answer:
Linear motion A bicycle going down a street having straight path, a falling apple.
Circular motion Revolution of the earth around the sun, motion of blades of a fan.
Oscillatory motion A simple pendulum, flapping of wings.
Question 10.
Observe different objects around you. It is easier to express the lengths of some objects in mm, some in cm and some in m . Make a list of three objects in each category and enter them in the table given below
Answer:
| Size | Objects |
| mm | Height of a lunch box lid |
| cm | Length of a pencil |
| m | Length of a desk |
Question 11.
A roller coaster track is made in the shape shown in the given figure. A ball starts from point A and escapes through point F. Identify the types of motion of the ball on the roller coaster and corresponding portions of the track.
Answer:
A to B – Linear motion
B to C – Oscillatory motion
C to E – Circular motion
E to F – Linear motion
Question 12.
Tasneem wants to make a metre scale by herself. She considers the following materials for it-plywood, paper, cloth, stretchable rubber and steel. Which of these, she should not use and why?
Answer:
She should not use stretchable rubber because it can stretch and deform during measurements which give inaccurate measurements.
Question 13.
Think, design and develop a card game on conversion of units of length to play with your friends.
Answer:
Make cards with different units of length (e.g. km, m, cm, mm ). Ask the players to draw cards one by one and convert the units correctly to win points. Add some more challenges to the game.
NCERT Solutions for Class 6 Science Chapter 5 Measurement of Length and Motion
Intext Questions
Question 1.
Would it be convenient to use the unit metre to measure larger lengths, such as the length of a railway track between two cities, or to measure smaller lengths, such as the thickness of a page of a book? (Page 83)
Answer:
It would not be convenient to use the unit metre to measure larger as well as smaller lengths. For measuring larger lengths, we use a larger unit called kilometre (km) and to measure smaller lengths like the thickness of a page, we use a smaller unit called millimetres (mm).
Question 2.
Why are some length measuring devices made up of flexible materials? (Page 86)
Answer:
Some length measuring devices are made up of flexible materials, so that curved lines or objects can be measured easily.
Question 3.
Suppose you are travelling on a ship which is moving at a constant speed along a straight line on a calm sea. Suppose there is no window on the ship. Is there any way that you can determine whether the ship is moving or stationary? (Page 91)
Answer:
On a windowless ship, we won’t be able to determine whether the ship is moving or stationary. Only by looking at something outside the ship, we can describe the motion. This indicates that motion is relative.
Let’s Investigate
Activity 1 (Page 86)
Aim : To measure the length of different objects around you.
Materials required Various objects like a comb, a pen, a pencil, an eraser, etc.
Procedures and Observations :
1. Take the objects one by one and measure their lengths using a metre scale.
2. Note down the measurements in the table given below (measurements may vary).
3. Write the unit along with the measured length.
| Object | Length of the object |
| Comb | 22 cm |
| Pencil | 15 cm |
| Eraser | 4 cm |
| Notebook | 25 cm |
Conclusion : We can conclude that the measured length of different objects is different. Also, a measurement consists of two parts-one part is a number and the other part is the unit of measurement.
Viva Questions :
1. Which instrument is suitable for measuring the length and width of a dining table?
2. What are the two parts of a measurement?
Activity 2 (Page 90)
Aim : To identify the objects are in motion or at rest.
Material required 3-4 blank papers and a pen.
Procedures and Observations :
1. Look around and prepare a list of five objects that are in motion and five objects that are at rest.
2. Record your observations in a table.
3. Think about how you decided whether an object was in motion or at rest.
4. Write your explanation (justification) in the table.
Conclusion : We can conclude that an object is said to be in motion, if its position changes with respect to the reference point with time. If an object is not changing its position with respect to the reference point with time, it is said to be at rest.
Viva Questions :
1. Out of the list that you have prepared, which object can be considered completely at rest?
2. Is the passenger inside a moving train at rest with respect to a person waving him from the platform?
Activity 3 (Page 91, 92)
Aim To identify the linear motion exhibited by the objects.
Materials required An eraser or a stone, a heavy box.
Procedures and Observations :
1. Take an eraser and drop it from a certain height.
2. Observe its motion.
3. Try to push a heavy box from one location to another in a room.
4. Observe its motion.
5. In both the cases, the objects seem to move in a straight line.
Conclusion When an object moves along a straight line, its motion is called linear motion.
Viva Questions :
1. Which type of motion is possessed by the students doing march past?
2. Do things always move along a straight line?
Activity 4 (Page 92-93)
Aim To identify the circular motion possessed by the objects.
Materials required A thread, an eraser or a potato.
Procedures and Observations :
1. Tie an eraser (or a potato) at one end of a thread.
2. Hold the other end of the thread with your hand and rotate rapidly as shown in the figure.
3. Observe its motion.
4. The eraser seems to move in a circular path.
Conclusion When an object moves along a circular path, its motion is called circular motion.
Viva Questions :
1. A boy is whirling a stone tied to a string in a horizontal circular path, which type of motion will be observed, if the string suddenly breaks?
2. What can you say about the position of an object exhibiting circular motion?
Activity 5 (Page 93)
Aim : To understand the objects possessing oscillatory motion.
Materials required A thread, an eraser or a potato.
Procedures and Observations :
1. Tie an eraser (or a potato) at one end of a thread.
2. Hang the eraser by holding the other end of the thread as shown in figure. Keep your hand steady.
3. Using the other hand, take the eraser slightly to one side and then release.
4. It should start moving to and fro.
Conclusion : We can conclude that when an object moves to and fro about some fixed position, its motion is called oscillatory motion.
Viva Questions :
1. Why does an oscillating object come to rest after sometime.
2. How does the eraser’s movement in this activity show that it’s experiencing oscillatory motion?
Activity 6 (Page 94)
Aim : To observe the oscillatory motion of a metal strip.
Materials required A thin metal strip or a metal scale, a few books or a brick and a table.
Procedures and Observations :
1. Take a thin metal strip of about 50 cm long.
2. Hold its one end pressed to a table. You may use a few books or a brick to hold it as shown in figure.
3. Press the free end of the strip slightly and let it go.
4. Observe the motion of this end of the strip.
5. It must go up and down showing a perfect example of oscillatory motion.
Conclusion : We can conclude that when an object moves to and fro about some fixed position, its motion is called oscillatory motion.
Viva Questions :
1. What is a term used to describe the oscillatory motion of the metal strip?
2. Why oscillatory motion is always periodic?
Activity 7 (Page 94, 95)
Aim : To identify different types of motion.
Materials required A picture of children’s park.
Procedures and Observations :
1. Look at the picture of a children’s park given here or visit a children’s park.
2. Observe different kinds of motions. Classify them as linear, circular or oscillatory motion.
3. List them in the table given below.
4. Give your justification for why you put each in a certain category.
Conclusion : We can conclude that different types of swing possess different types of motion.
Viva Questions :
1. Kids on a merry-go-round possess circular motion while the merry-go-round itself exhibits which type of motion?
2. Mention the types of motion possessed by a rolling ball.
Do it Yourself (DIY)
To understand the meaning of motion by observing an ant.