Motion and Measurement of Distances | Science 6th | Chapter 10 | Questions and Answers

JANDKNCERT | Science 6^th |

Motion and Measurement of Distances | Science 6th | Chapter 10 | Questions and Answers

 

Chapter 10: Motion and Measurement of Distances

Dear Students, in Chapter 9, you learnt about The Living Organisms and Their Surroundings, in which you learnt about the habitat of living organisms. You learnt adaptation of organisms to a particular place, biotic and abiotic components, and characteristic features of living organisms for getting their food.

In this chapter, you will learn about the Motion and Measurement of Distances. The following points will help you to understand this chapter easily.

o   Different modes of transport are used to go from one place to another.

o   In ancient times, people used the length of a foot, the width of a finger, the distance of a step as units of measurement. This caused confusion and a need to develop a uniform system of measurement arose.

o  Now, we use the International System of Unit (SI unit). This is accepted all over the world.

o   The metre is the unit of length in the SI unit.

o   Motion in a straight line is called rectilinear motion.

o   In a circular motion, an object moves such that its distance from a fixed point remains the same.

o   Motion that repeats itself after some period, of time, is called periodic motion.

 

Let us try to answer some questions taken from the NCERT Book of Science Class 6th. This Exercise is taken from the same book.

 

Exercises

Q1. Give two examples each, of modes of transport used on land, water and air.

Ans. Examples of modes of transport:

Land Transport: Train, Bus

Water Transport: Ship, Boat

Air Transport: Aeroplane, Helicopter

Q2. Fill in the blanks:

(i) One metre is ______________ cm.

(ii) Five kilometres is ______________ m.

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

(iv) Motion of needle of a sewing machine is ______________.

(v) Motion of a wheel of a bicycle is______________.

(vi) The 1/1000 part of meter is called____________.

(vii) 1000 times the length of meter is called________.

Ans.

(i) One metre is 100 cm.

(ii) Five kilometres is 5000 m.

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

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

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

(vi) The 1/1000 part of meter is called millimetre.

(vii) 1000 times the length of meter is called kilometre.

Q3. Why can a pace or a footstep not be used as a standard unit of length?

Ans. We cannot use a pace or a footstep as a standard unit because it causes confusion and results, the variation in the measurement.

Q4. Arrange the following lengths in their increasing magnitude:

1 metre, 1 centimetre, 1 kilometre,1 millimetre.

Ans. 1 millimetre, 1 centimetre, 1 metre, 1 kilometre

Q5. The height of a person is 1.65 m. Express it into cm and mm.

Ans. Height of a person = 1.65 m

(1 m = 100 cm)

Therefore;

Height of a person in (cm) = 1.65 x 100 cm

= 165.00 cm

= 165 cm

(1 m = 1000 mm)

Therefore;

Height of a person in (mm) = 1.65 x 1000mm

= 1650.0 mm

= 1650 mm

(Note: m = metre, cm = centimetre, mm = millimetre)

Q6. The distance between Radha’s home and her school is 3250 m. Express this distance into km.

Ans.

Distance between Radha’s Home and her School = 3250 m

We know that,

1000 m = 1 km

Therefore; 3000 m = 3 km

3250 m = 3.25 km

Explanation:

1000 m = 1 km

1 m = 1 / 1000 km

3250 m = 1 / 1000 km x 3250

= 3250 / 1000 km

= 3.25 km

Q7. 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?

Ans.

Reading at one end of Needle = 3.0 cm

Reading at the other end = 33.1 cm

Length of needle = 33.1 cm – 3.0 cm

= 30.1 cm

Q8. Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.

Ans.

Similarities between the motion of bicycle and blades of fan:

Both wheels of a bicycle and blades of a ceiling fan show circular motion.

Difference:

The bicycle moves along a straight line thus show rectilinear motion, while as the fan remains fixed thus does not show rectilinear motion.

Q9. 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?

Ans. We cannot use an elastic measuring tape to measure distance because it stretches when pulled on the ends while measuring the distance. When measuring with elastic tapes we have to keep many things in mind. We have to tell the person whether the distance was measured after a stretch or not. This may result in variation in the measurement. Hence it is not wise to measure with elastic tapes.

Q10. Give two examples of periodic motion.

Ans. Two examples of Periodic Motion are:

1. Motion of a pendulum, and 2. The motion of a child on a swing

Q11. You are sitting in a moving bus and looking out? Are you in a state of motion or rest? Explain.

Ans. When sitting in a moving bus, we are both at rest and in a state of motion. We are in a state of motion, with respect, to the trees that are passing by with the moving of the bus. But at the same time, we are at rest with respect, to the passengers and seats of the bus. This is what, Law of Inertia, tells us, that a body is at rest or in uniform motion unless and until an external force is applied on it to move.

Q12. Giving at least two examples, define the terms.

a. Rectilinear motion

Ans.

1. Falling of a stone

2. Motion of a vehicle on a straight road

b. Rotatory motion

Ans.

1. Rotation of fan blades

2. Rotation of hands of a clock

c. Oscillatory motion

Ans.

1. Motion of a pendulum

2. Motion of a child on a swing

d. Periodic motion

Ans.

1. Motion of strings of a guitar

2. Motion of a child on a swing