Chapter 5 Solutions — Measurement of Length and Motion

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1. 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. Column I:

   • (a) Distance between Delhi and Lucknow
   • (b) Thickness of a coin
   • (c) Length of an eraser
   • (d) Length of school ground Column II:
   • (i) centimetre
   • (ii) kilometre
   • (iii) metre
   • (iv) millimetre
2. 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.
   • (ii) Any object which is changing its position with respect to a reference point with time is said to be in motion.
   • (iii) 1 km = 100 cm
3. 3.
   Which of the following is not a standard unit of measuring length?

   • (i) millimetre
   • (ii) centimetre
   • (iii) kilometre
   • (iv) handspan
4. 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.
5. 5.
   Suppose the distance between your school and home is 1.5 km. Express it in metres.
6. 6.
   Take a tumbler or a bottle. Measure the length of the curved part of the base of glass or bottle and record it.
7. 7.
   Measure the height of your friend and express it in

   • (i) metres
   • (ii) centimetres and
   • (iii) millimetres.
8. 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.
9. 9.
   Give two examples each for linear, circular and oscillatory motion.
10. 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.
11. 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.
12. 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?
13. 13.
    Think, design and develop a card game on conversion of units of length to play with your friends.