and Measurement of distances
Q20. Why can't hand span and cubit be used as standard units?
Hand span and cubit cannot be used as standard units because everyone's body
parts could be of slightly different sizes which cause confusion in measurement.
Q21. Why we should not use an elastic tape for measuring the
We should not use an elastic tape for measuring the length because elastic
measuring tape is stretchable and the length of the tape may change on
stretching. Thus, an elastic tape gives wrong measurement.
Q22. State the 3 precautions
which should be taken while using a metre scale to measure length.
In taking measurement of a length, we need to take care of the following:
Place the scale in contact with the object
along its length.
Avoid taking measurements using broken
must be exactly in front of the point where the measurement is to be taken.
Q23. How people travelled from one place to another in earlier
times before the discovery of wheel?
Ans. Long ago people used to move only on foot and
carry goods on their back or using animals. For transport along water routes,
boats were used from ancient times.
Q24. Write the steps to measure the length of objects using
Steps to measure the length of objects using measuring tape:
Place the measuring tape in contact with
the object along its length.
Take the measurements from the zero mark of
the measuring tape.
the reading at the other end of the object.
gives the measure of the length of the object.
Q25. Write the unit for measuring the following:
Distance between Noida and Gurugram - Kilometre
Thickness of compact disc (CD) - Millimetre
Length of a sharpener - Centimetre
Length of a tie – Centimetre
Length of a sari – Metre
Q26. Name the device used to measure the following:
Size of shoulder – Measuring tape
Size of waist – Measuring tape
Height of a pole – Measuring tape
Weight of an object – Weighing balance
Fabric for a dress – Measuring tape or
Circum ference of a round platform – A
long thread or Measuring tape
Q27. “Pace or footstep cannot be used as standard unit of
The size of foot varies from one person
to another. Length measured by footsteps of two different persons may not be equal.
Thus foot step is not a fixed quantity as it differs from person to person.
Hence, it cannot be used as standard unit of length.
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.?
14.5 km = 14.5 x 1000 = 14500m
covers 30,000m in 1 hr.
covers 1m in 1/30,000 hr.
covers 14500m in 1/30,000 x 14500 = 0.4833 hrs.
0.4833 x 60 = 29 minutes
Q29. How invention of wheel made a great change in modes of
The invention of wheel brought in a great change in the modes of transport.
People employed carts and chariots to travel from one place to another. It made
the transportation of goods and people much easier. Modern means of transport
such as cars, buses, trains and airplanes allow us to travel faster than those used
in earlier times.