Class 6 | Science | Chapter 10 | Motion and Measurement of Distances | NCERT Solutions

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

Answer 1 Land transport : Bus, train, motorbike.

Water transport : Boat, ship, steamer.

Air Transport : Aeroplane, Helicopter.

Question 2. Fill in the blanks:
(i) One metre is ______________ cm.
(ii) Five kilometre is ______________ m.
(iii)Motion of a child on a swing is ______________.
(iv)Motion of the needle of a sewing machine is ______________.
(v) Motion of wheel of a bicycle is______________.

Answer 2 (i) One metre is 100 cm.

(ii) Five kilometre is 5000 m.

(iii)Motion of a child on a swing is periodic motion.

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

(v) Motion of wheel of a bicycle is circular motion.

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

Answer 3 A pace or a footstep should not be used as a standard unit of length because the length of pace and footstep vary from person to person. This will lead to confusion while measuring the lengths by different persons.

Question 4. Arrange the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre,1 millimetre.

Answer 4 1 millimetre < 1 centimetre< 1 metre< 1 kilometre.

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

Answer 5 1 metre = 100 cm and 1 metre = 1000 mm

So, 1.65 m = 1.65 × 100 = 165 cm

1.65 m = 1.65 × 1000 = 1650 mm

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

Answer 6 1000m = 1 Km

3250 m = 3250/1000 Km

= 3.250 Km

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 7 The length of the needle = 33.1 cm – 3.0 cm = 30.1 cm

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

Answer 8

Similarity

1) Both show circular motion.

2) Both are fixed at a point

Difference

Bicycle shows a rectilinear motion whereas a ceiling fan does not.

Question 9. Why would you not like to use a measuring tape made of an elastic material like rubber to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with such a tape?

Answer 9 An elastic tape is flexible and can be stretched.It will show different lengths for same measurement which leads to incorrect measurements.

Question 10. Give two examples of periodic motion.

Answer 10 Rotation of Earth, Pendulum