NCERT Solution for Class 6 Chapter 5 - Measurement of Length and Motion

NCERT Solutions For Class 6 Science Measurement of Length and Motion: Exercise Question and Answer

Question 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 :

Question 2.1: Read the following statements and mark True (T) or False (F) against each.

The motion of a car moving on a straight road is an example of linear motion. [ ]

Answer: True

Question 2.2: Read the following statements and mark True (T) or False (F) against each.

Any object which is changing its position with respect to a reference point with time is said to be in motion. [ ]

Answer: True

Question 2.3: Read the following statements and mark True (T) or False (F) against each.

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) handspan

Answer: (iv) handspan

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:

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

Answer : ∵ 1 km = 1000 metres

∴ 1.5 km = 1.5 × 1000 = 1500 metres

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

Answer: Hint: Use a flexible measuring tape or a piece of string to measure the length of the curved part of the base of the tumbler, then measure the string against a ruler.

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

Answer: Hint: Measure the height using a metre scale and express it in:

• Metres (e.g., 1.4 m)
• Centimetres (e.g., 140 cm)
• Millimetres (e.g., 1400 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 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: Hint: Measure the diameter of the coin and the length of the notebook. Divide the length of the notebook by the diameter of the coin to estimate the number of coins required. Say the diameter of the coin is 2 cm and the length of the notebook is 18 cm . Then $\left(\frac{18}{2}\right)=9$ coins can be placed side to side along the length of the notebook. Verify by placing the coins end-to-end and measuring again.

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

Answer:

• Linear motion: A car moving on a straight road, an eraser dropping straight down.
• Circular motion: A merry-go-round, the motion of a whirling stone tied to a thread.
• Oscillatory motion: A swinging pendulum, the motion of a metal strip pressed and released.

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 Table 5.6.

Table 5.6: Sizes of objects around us

Answer: Classify objects by the convenience of measuring in mm, cm, and m:

Question 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 corresponding portions of the track.

Answer: Portions of the track and corresponding types of motion:

• A to B: Linear motion
• B to C: Circular motion (loop)
• C to D 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 should she not use and why?

Answer: Tasneem should not use stretchable rubber because it can change length when stretched, leading to inaccurate measurements. Plywood, cloth, paper, and steel are more suitable as they maintain consistent lengths.

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

Answer: Create cards with different lengths and corresponding units (mm, cm, m, km). Each card can have a length in one unit and players must match it to its equivalent in another unit. For example, a card with “100 cm” would match with “1 m”.