Q20. Why can't hand span and cubit be used as standard units?
Q21. Why we should not use an elastic tape for measuring the length?
Q22. State the 3 precautions which should be taken while using a metre scale to measure length.
Q23. How people travelled from one place to another in earlier times before the discovery of wheel?
Q24. Write the steps to measure the length of objects using measuring tape.
Q25. Write the unit for measuring the following:
i. Distance between Noida and Gurugram - _______________
ii. Thickness of compact disc (CD) - ____________
iii. Length of a sharpener - ____________
iv. Length of a tie – _______________
v. Length of a sari – ____________
Q26. Name the device used to measure the following:
i. Size of shoulder – _____________
ii. Size of waist – _______________
iii. Height of a pole –______________
iv. Weight of an object – _______________
v. Fabric for a dress – _________________
vi. Circumference of a round platform – __________________________
Q27. “Pace or footstep cannot be used as standard unit of length”. Comment
Q28. Distance between Ayush’s home and his office is 14.5 km. How much time will he take to reach his workplace if he is travelling by a car with a speed of 30,000 m/hr.?
Q29. How invention of wheel made a great change in modes of transport?