Motion and Measurement of Distances: science class six


NCERT Exercise Solution

Question (1) Give two examples each, of modes of transport used on land, water and air.

Answer

Modes of transport on land: Motorcycle, Car

Modes of transport on water: A boat, A ship

Modes of transport in air: An aeroplane, A helicopter

Question (2) Fill in the blanks:

(i) One meter is ________ cm.

Answer

One meter is 100 cm.

(ii) Five kilometre is _____ m.

Answer

Five kilometer is 5000 m.

(iii) Motion of a child on a swing is _________.

Answer

Motion of a child on a swing is Periodic Motion.

(iv) Motion of the needle of a sewing machine is ______.

Answer

Motion of the needle of a sewing machine is Periodic Motion cm.

(v) Motion of wheel of a bicycle is ________.

Answer

Motion of wheel of a bicycle is Circular Motion cm.

Question (3) Why can a pace or a footstep not be used as a standard unit of length?

Answer

A pace or a footstep not be used as a standard unit of length because the length of the pace or a footstep differs from person to person. Hence this will give the difference in measurement.

Question (4) Arrange the following lengths in their increasing magnitude:

1 meter, 1 centimeter, 1 kilometer, 1 millimeter

Answer

1 millimeter < 1 centimeter < 1 meter < 1 kilometer

Question (5) The height of a person is 1.65 m. Express it into cm and mm.

Answer

We know that

1 m = 100 cm

And, 1 cm = 10 mm

Thus, 1 m = 100 × 10 mm = 1000 mm

Therefore, 1.65 m = 1.65 × 100 cm = 165 cm

⇒ 1.65 m = 165 cm Answer

And, 1.65 m = 1.65 × 1000 mm = 1650 mm

⇒ 1.65 m = 1650 mm Answer

Question (6) The distance between Radha's home and her school is 3250 m. Express this into km.

Answer

We know that, 1 km = 1000 m

Therefore, 1 m = 11000 km

Therefore, 3250 m = 32501000 km

⇒ 3250 m = 3.25 km Answer

Question (7) While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?

Answer

Given, initial reading = 3.0 cm

And final reading = 33.1 cm

Therefore, length of the needle = Final reading – Initial reading

= 33.1 cm – 3.0 cm = 30.1 cm

Thus, length of the knitting needle = 30.1 cm Answer

Question (8) Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.

Answer

Similarities between motion of a bicycle and a ceiling fan

The motion of the tyre or a point on the wheel of a bicycle is in circular motion.

And the motion of the ceiling fan also in circular motion.

Difference between motion of a bicycle and a ceiling fan

The motion of a bicycle can be rectilinear motion when cycle runs along a straight line.

But, the motion of a ceiling fan cannot be rectilinear.

Question (9) Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?

Answer

An elastic measuring tape cannot have a fixed length because it can be stretched this can give incorrect measurement of length. So an elastic measuring tape cannot be used to measure a distance.

If a distance is measured using an elastic measuring tape, then I will tell the another person that the measured length would not be correct because the elastic measuring tape does not have a fixed length.

Question (10) Give two examples of periodic motion.

Answer

Two examples of Periodic Motion

(a) Motion of a pendulum

(b) Motion of the needle of a sewing machine

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