Chapter 5 of Class 6 Science, Measurement of Length and Motion, explains the basic features that make an organism live. Through simple questions and answers, students can easily understand this chapter.

Let us enhance our learning

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1. Some lengths are given in Column I of Table 5.5. Some units are given in Column II. Match the lengths with the units suitable for measuring those lengths.

Answer:

• Distance between Delhi and Lucknow — kilometres
  
• Thickness of a coin — millimetre
  
• Length of an eraser — centimetre
  
• Length of school ground — metres
  

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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 (T)

(ii) Any object which is changing its position with respect to a reference point with time is said to be in motion.
Answer: True (T)

(iii) 1 km = 100 cm
Answer: False (F)

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3. Which of the following is not a standard unit of measuring length?

(i) millimetre (ii) centimetre (iii) kilometre (iv) handspan

Answer: (iv) handspan

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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 (Example):

Scale	Smallest Value
15 cm ruler	1 mm
Meter scale	1 mm
Measuring tape	1 mm

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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 metres

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6. Take a tumbler or a bottle. Measure the length of the curved part of the base of the glass or bottle and record it.

Answer:
The curved length can be measured using a thread.
Place the thread along the curved part, then measure the thread with a scale.

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7. Measure the height of your friend and express it in (i) metres, (ii) centimetres and (iii) millimetres.

Answer (Example):
(i) 1.5 m
(ii) 150 cm
(iii) 1500 mm

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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 whole 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 scale.

Answer (Example):
Length of notebook = 21 cm
Diameter of coin = 2 cm
21 ÷ 2 ≈ 10–11 coins required.

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9. Give two examples each for linear, circular and oscillatory motion.

Answer:

Linear motion:

• Car moving on a straight road
  
• A train moving on a straight track
  

Circular motion:

• Ceiling fan
  
• Hands of a clock
  

Oscillatory motion:

• Pendulum
  
• Swing
  

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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 Table 5.6.

Answer:

mm: Thickness of coin, paper thickness, pencil tip
cm: Eraser, notebook, spoon
m: Door, classroom, tree

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11. A rollercoaster track is made in the shape shown in Fig. 5.19. A ball starts from point A and escapes through point F. Identify the types of motion of the ball on the rollercoaster and the corresponding portions of the track.

Answer:
A to B — Linear motion
B to C — Curvilinear motion
C to E — Circular motion
E to F — Linear motion

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📘 Page 3

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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 should she not use and why?

Answer:
She should not use cloth and stretchable rubber because they can stretch and give incorrect measurements.

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13. Think, design and develop a card game on the conversion of units of length to play with your friends.

Answer:
Make cards with units like 1 km, 1000 m, 100 cm, 10 mm.
Players match correct conversions.
The player who matches correctly wins.