Measurement of Length and Motion – Very Short Answer Type Questions
CBSE Class 6 Science — Chapter 5: Measurement of Length and Motion
50 Very Short Answer Type Questions with Answers — NCERT-aligned for CBSE Class 6 revision.
Quick Revision — 50 Very Short Q&A
These questions are grouped topic-wise for easy study. Answers are short and NCERT-focused.
Units & Instruments (1–10)
1. What is the SI unit of length?
Metre (m).
2. How many centimetres are in 1 metre?
100 cm in 1 m.
3. How many millimetres are in 1 metre?
1000 mm in 1 m.
4. How many metres make 1 kilometre?
1000 m = 1 km.
5. Name a tool to measure short lengths up to 30 cm.
Ruler.
6. Which instrument is used to measure long curved distances?
Measuring tape (tape measure).
7. Which tool is useful for measuring distances on roads?
Odometer or measuring wheel (trundle wheel).
8. What is the smallest division on a typical school ruler?
1 millimetre (mm) is usually the smallest division.
9. Why should you start reading from the zero mark on a ruler?
Because the ruler edge may not be exactly at zero; starting at zero gives accurate measurement.
10. What unit would you use to measure the length of a classroom?
Metres (m).
Measurement Techniques (11–20)
11. How do you measure the length of a pencil?
Place pencil along ruler and read the mark at the end starting from 0.
12. How do you measure a curved line like a rope?
Use a measuring tape or lay rope on a ruler and mark segments, or use a trundle wheel for long curves.
13. How should a measuring tape be held while measuring?
Keep it straight and taut without sagging to get accurate length.
14. Why repeat measurements in experiments?
To reduce errors and get a more reliable average value.
15. What to do if a length falls between two marks?
Estimate to the nearest smaller division and state it as an estimate (e.g., 4.6 cm).
16. How to measure the diagonal of a book?
Use a ruler or measuring tape from one corner to the opposite corner in a straight line.
17. What unit is used for measuring tiny objects like insects?
Millimetres (mm) or centimetres (cm), depending on size.
18. How to ensure a ruler is correctly aligned?
Place it along the object with the zero mark at one end and keep it parallel to the object.
19. How to convert metres into centimetres?
Multiply metres by 100 (1 m = 100 cm).
20. How to convert centimetres into metres?
Divide centimetres by 100 (e.g., 150 cm = 1.5 m).
Motion Basics (21–30)
21. What is motion?
Motion is the change in position of an object with time.
22. Give an example of motion.
A car moving along a road or a person walking are examples of motion.
23. What is distance?
Distance is the total path length travelled by an object.
24. What is displacement (simple)?
Displacement is the straight-line distance from start to end point (with direction) — introduced simply.
25. How is time measured in motion experiments?
Using a stopwatch or clock in seconds, minutes or hours.
26. What instruments help observe motion in class?
Stopwatch, metre scale, measuring tape and toy cars.
27. What does a speedometer show?
The speed of a vehicle at a given instant (usually in km/h).
28. Why record units when measuring?
Units tell what the number represents and ensure correct interpretation (e.g., m, cm, s).
29. What is the importance of consistent units?
Consistent units prevent calculation errors (convert units before using formulas).
30. Does motion always require a force?
Yes, a force is needed to start motion (basic idea); friction and other factors may affect motion.
Speed & Calculations (31–40)
31. What is speed?
Speed is how fast an object moves — distance covered per unit time.
32. Write the formula for speed.
Speed = Distance / Time (v = d / t).
33. If a car travels 60 km in 2 h, what is its speed?
Speed = 60 km / 2 h = 30 km/h.
34. If a runner covers 100 m in 20 s, what is the speed?
Speed = 100 m / 20 s = 5 m/s.
35. How to find average speed?
Average speed = Total distance / Total time for the journey.
36. What are common units of speed?
m/s (metres per second) and km/h (kilometres per hour).
37. Convert 10 m/s to km/h (simple method: ×3.6).
10 m/s × 3.6 = 36 km/h.
38. Convert 72 km/h to m/s (÷3.6).
72 ÷ 3.6 = 20 m/s.
39. A bike travels 30 km in 1.5 h. What is its speed?
Speed = 30 / 1.5 = 20 km/h.
40. When should you convert units before calculation?
When distance and time are in different unit systems (e.g., m with hours) — convert to consistent units first.
Practical & Common Errors (41–50)
41. What is a trundle wheel used for?
Measuring long distances on the ground by rolling the wheel and counting revolutions.
42. Why should a measuring tape be straight when measuring?
To avoid extra length caused by sagging; straight tape gives accurate measurement.
43. What mistake occurs if you read a ruler from the edge?
You may get an incorrect reading if the ruler edge is not aligned with zero mark.
44. How to improve accuracy in timing experiments?
Repeat trials, use a stopwatch, start and stop timing precisely at motion start/end.
45. What should you write with every measurement?
Always write the number with its unit (e.g., 5 m, 20 s).
46. How to measure the length of a curved path on paper?
Use a thread to follow the curve, straighten the thread and measure it with a ruler.
47. What is meant by 'estimate' in measurement?
An approximate reading between two marks when exact value is not available; give nearest value and unit.
48. Why convert minutes to hours when using km/h?
Because km/h uses hours as the time unit; convert minutes to hours for consistent units.
49. How many seconds are there in 2 minutes?
2 minutes = 120 seconds.
50. Give one tip to get accurate measurements in experiments.
Always take multiple readings and use the average, and ensure measuring instruments are properly placed.