NCERT Solutions for Class 6 Chapter 5 Measurement of Length and Motion – MyNoteswala

NCERT Intext Questions – Measurement of Length and Motion (Class 6)

📏 Q.1. Would it be convenient to use the unit metre to measure larger or smaller lengths?

(Page No. 83)

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Answer: No, using the metre would not be convenient in either case.

✨ For very large distances (like the length of a railway track between two cities), we use 🟩 kilometres (km).

✨ For very small lengths (like the thickness of a page), we use 🟦 millimetres (mm).

👉 Example:
🚄 Distance between Jaipur and Delhi = about 🔵 270 km
📖 Thickness of a notebook page = about 🟣 0.1 mm

💡 Did You Know? 📏 The kilometre (km), metre (m), centimetre (cm), and millimetre (mm) are all part of the 🌍 metric system, which makes conversions super easy:
➡️ 1 km = 1000 m
➡️ 1 m = 100 cm
➡️ 1 cm = 10 mm

🪨 Q.2. What do such kilometre stones indicate? How could Padma conclude that she was getting closer to her destination?

(Page No. 89)

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Answer: 🪧 Kilometre stones placed along roads show the distance (in kilometres) from a particular city or location.

They help travellers know how far they are from their destination.

Padma noticed that the numbers on the kilometre stones were decreasing as she moved ahead. This helped her understand that she was getting closer to her destination.

👉 Example:
• Jaipur – 50 km
• Jaipur – 30 km
• Jaipur – 10 km
She could easily tell that Jaipur was approaching because the numbers were going down.

💡 Did You Know? 📍 The small stones or signboards on highways are called milestones or kilometre stones.
🛣️ They usually have yellow tops on national highways and green tops on state highways in India!

🚶‍♀️ Q.3. Does this mean that the position of Padma, with respect to the reference point, is changing with time? When does the position of an object change with respect to a reference point? Does it change when an object is moving?

(Page No. 89)

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Answer: Yes, the position of Padma with respect to the reference point is changing with time because she is moving along the road.

📍 The position of an object changes with respect to a reference point when the object moves from one place to another.

If the object does not move, its position remains the same.

👉 Example:
• If Padma walks from a tree towards a shop, her position keeps changing with time.
• But if she stands still beside the shop, her position does not change.

💡 Did You Know? 🧭 In physics, when an object changes its position with time relative to a fixed point, it is said to be in motion. That’s how we know something is moving — because its distance from a reference point changes!

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

Column I	Column II
Distance between Delhi and Lucknow	centimetre
Thickness of a coin	kilometre
Length of an eraser	metre
Length of school ground	millimetre

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Answer: The correct matching of lengths with suitable units is given below.

Column I	Column II
Distance between Delhi and Lucknow	Kilometre
Thickness of a coin	Millimetre
Length of an eraser	Centimetre
Length of school ground	Metre

💡 Did You Know? 📏 The metric system helps us choose the right unit for different measurements — millimetres for tiny objects, metres for medium lengths, and kilometres for long distances!

🧭 Q.2. Read the following statements and mark True (T) or False (F) against each.

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Answer:

(i) The motion of a car moving on a straight road is an example of linear motion. — ✅ True

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

(iii) 1 km = 100 cm — ❌ False

💡 Did You Know? 📏 The correct conversion is 1 kilometre = 1000 metres = 100,000 centimetres. Always remember: 1 km = 1000 m and 1 m = 100 cm.

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

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(i) millimetre

(ii) centimetre

(iii) kilometre

(iv) handspan

Answer: (iv) handspan

💬 Explanation:
🖐️ The handspan is not a standard unit because it can differ from person to person.
Everyone’s hand size is different, so measurements using handspan are not accurate.
📏 Standard units like millimetre (mm), centimetre (cm), and kilometre (km) are fixed and universal, used everywhere for consistency.

💡 Did You Know? Before standard units were invented, people used non-standard units like handspan, cubit (elbow to fingertip), and foot — but they caused confusion, so the metric system was introduced!

📐 Q.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.

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Answer: Here’s a sample table showing different measuring tools and the smallest value each can measure 👇

🧰 Measuring Tool	📏 Place Found	🔢 Smallest Value That Can Be Measured	💬 Used For
Ruler (Scale)	School geometry box	1 millimetre (mm)	Measuring small lengths (books, pencils)
Measuring Tape	Home / Toolbox	1 millimetre (mm) or 0.1 cm	Measuring longer distances (cloth, furniture)
Steel Tape (Engineer’s tape)	Workshop / School lab	1 millimetre (mm)	Measuring precise lengths of metal rods or objects
Tailor’s Tape	Home (sewing kit)	1 millimetre (mm)	Measuring cloth or body measurements
Meter Rod	School science lab	1 centimetre (cm)	Measuring classroom objects or table length

💡 Did You Know? 📏 The smallest value that a scale can measure is called its least count. For most normal rulers, the least count is 1 mm, but for very fine instruments like a vernier caliper, it can be 0.01 mm!

📏 Q.5. Suppose the distance between your school and home is 1.5 km. Express it in metres.

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Answer: We know that,

👉 1 kilometre (km) = 1000 metres (m)

So,

1.5 km = 1.5 × 1000 m = 1500 metres

✅ Therefore, the distance between school and home = 1500 m

💡 Did You Know? 🚶‍♂️ On average, a person walks about 80 metres in one minute — so, to cover 1.5 km, it takes roughly 18–20 minutes of walking!

🧴 Q.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.

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Answer: We can measure the curved part using a thread instead of a ruler.

Steps:
1️⃣ Take a piece of thread and place it along the curved edge of the base.
2️⃣ Mark the starting and ending points on the thread.
3️⃣ Straighten the thread and measure its length with a scale.

🧵 Example:
If the curved thread length measures 25 cm, then 👉 The length of the curved part = 25 cm.

💡 Did You Know? When you use a thread to measure curved surfaces, you are finding the circumference — that’s how we also measure the round edges of plates or lids!

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

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Answer: Let’s say the height of your friend is 1.4 metres.

(i) In metres (m) = 1.4 m

(ii) In centimetres (cm) = 1.4 × 100 = 140 cm

(iii) In millimetres (mm) = 140 × 10 = 1400 mm

✅ Therefore, height = 1.4 m = 140 cm = 1400 mm

💡 Did You Know? 🏃‍♀️ The average height of a Class 6 student is around 1.4 to 1.5 metres — which equals about the height of a door handle!

🪙 Q.8. You are given a coin. Estimate how many coins are required to be placed one after the other, lengthwise, without leaving any gap, to cover the whole length of one side of a notebook. Verify your estimate by measuring with a 15-cm scale.

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Answer:

Step 1: Estimate
Let’s say the notebook side = 15 cm, and the diameter of one coin ≈ 2.5 cm.
👉 Estimated number of coins = 15 ÷ 2.5 = 6 coins.

Step 2: Verify
Place coins in a line along the notebook side. If the actual count = 6 coins, the estimate was correct!

💡 Did You Know? 📘 Activities like this help you compare measurements practically — a fun way to understand division and estimation in real life!

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

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Answer:

🔹 Type of Motion	🌀 Examples
Linear Motion (moving in a straight line)	(i) A car moving on a straight road 🚗 (ii) A train moving on a straight track 🚆
Circular Motion (moving around a fixed point)	(i) The blades of a fan 🌀 (ii) The hands of a clock ⏰
Oscillatory Motion (back-and-forth movement)	(i) A swinging pendulum ⏳ (ii) A child on a swing 🎠

💡 Did You Know? 🧭 Earth’s rotation around its axis is an example of circular motion, while its back-and-forth shaking during earthquakes is oscillatory motion!

📏 Q.10. Observe different objects around you. It is easier to express the lengths of some objects in millimetres (mm), some in centimetres (cm), and some in metres (m). Make a list of three objects in each category and enter them in the given table.

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Answer:

🧩 Size (Unit)	📘 Examples of Objects
mm (millimetres)	✏️ Thickness of a pencil lead 📄 Thickness of a page 💍 Diameter of a small bead
cm (centimetres)	📏 Length of an eraser 📚 Width of a notebook 🍎 Diameter of an apple
m (metres)	🚪 Height of a door 🪑 Length of a classroom 🚶‍♂️ Height of a person

💡 Did You Know? 📐 Scientists and engineers use different metric units depending on the size of the object — from micrometres (μm) for bacteria to kilometres (km) for long distances like roads and rivers!

🎢 Q.11. A roller coaster track is made in the shape shown in the 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 the corresponding portions of the track.

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Answer: The ball shows different types of motion on different parts of the track:

🔤 Portion of Track	⚙️ Type of Motion	💬 Explanation
A → B → C	Linear Motion 🛤️	The ball moves in a straight, downward path along the sloping track.
C → D → E	Circular Motion 🔄	The ball moves in a loop — going around a curved path forming a circle.
E → F	Linear Motion 🧭	The ball again moves in a straight line after leaving the loop.

💡 Did You Know? 🎢 Roller coasters are real-life examples of combined motion — they include linear, circular, and curved motion all in one ride! Engineers use the laws of motion and gravity to design safe and thrilling coaster loops!

📏 Q.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?

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Answer: Tasneem should not use cloth and stretchable rubber.

Reason: Cloth and rubber are flexible and stretchable, so their length changes when pulled or stretched. They cannot give accurate measurements.

Best materials: She should use steel or plywood, because they are rigid and non-stretchable, ensuring correct and reliable measurements.

💡 Did You Know? 📏 Measuring tapes used by engineers and carpenters are usually made of steel because it does not stretch and gives precise readings even for long distances!

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

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Answer: Measure Master — a simple card game to practice length conversions.

Materials: 20–30 cards (paper or thin cardboard), pen/marker.

How to make cards:
• Write a conversion question on the front and the correct answer on the back.
• Examples: Front: “1 km = ? m” → Back: “1000 m”; Front: “50 cm = ? mm” → Back: “500 mm”.

How to play:
1️⃣ Shuffle cards and keep them face down.
2️⃣ Each player picks a card and says the conversion aloud.
3️⃣ Correct answer → 1 point. Wrong → 0 points (optionally show the correct answer).
4️⃣ After all cards are used, the highest score wins.

Bonus round idea: Add “Challenge Cards” (e.g. “Convert 2.5 km to cm” or “Change 1200 mm to m”) with a 10-second time limit for extra points.

💡 Did You Know? Games like this make metric conversions easy to remember and turn learning into a fun group activity!

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