Ans. 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.
Ans. 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.
Ans. In taking measurement of a length, we need to take care of the following:
i. Place the scale in contact with the object along its length.
ii. Avoid taking measurements using broken scale.
iii. Eye must be exactly in front of the point where the measurement is to be taken.
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.
Ans. Steps to measure the length of objects using measuring tape:
i. Place the measuring tape in contact with the object along its length.
ii. Take the measurements from the zero mark of the measuring tape.
iii. Note the reading at the other end of the object.
iv. This gives the measure of the length of the object.
i. Distance between Noida and Gurugram - Kilometre
ii. Thickness of compact disc (CD) - Millimetre
iii. Length of a sharpener - Centimetre
iv. Length of a tie – Centimetre
v. Length of a sari – Metre
i. Size of shoulder – Measuring tape
ii. Size of waist – Measuring tape
iii. Height of a pole – Measuring tape
iv. Weight of an object – Weighing balance
v. Fabric for a dress – Measuring tape or Metre scale
vi. Circum ference of a round platform – A long thread or Measuring tape
Ans. 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.
Ans. 14.5 km = 14.5 x 1000 = 14500m
Car covers 30,000m in 1 hr.
Car covers 1m in 1/30,000 hr.
Car covers 14500m in 1/30,000 x 14500 = 0.4833 hrs.
= 0.4833 x 60 = 29 minutes
Ans. 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.
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