 # Motion and Measurement of Distances

Exercise:

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

Modes of transport on land: bus, train, truck, car. etc.

Modes of transport on water: boat, ship, steamer. etc.

Modes of transport on air: aeroplane, helicopter. etc.

2). Fill in the blanks:

(i). One metre is 100 cm.

(ii). Five kilometres is 5000 m.

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

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

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

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

Pace or footstep cannot be used as a standard unit of length as they differ from person to person.

4). Arrange the following lengths in their increasing magnitude:

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

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

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

1.65 m = 165 cm

1.65 m = 1650 mm

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

3250 m = 3 km 250 m.

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?

The length of the needle = 33.1-3.0 = 30.1 cm

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

Similarities: Both the wheel of a bicycle and a ceiling fan are in performing circular motion

Difference: The ceiling fan does not change its position whereas the bicycle moves forward in rectilinear motion.

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?

An elastic material like rubber cannot be used in measuring length because

i). Its length depends upon the force by which it is stretched.

ii). Its length varies from person to person.

iii). Even per the same person its length may change if stretched 2 to 3 times.

10). Give two examples of periodic motion.

A branch of a tree moving to and fro, the motion of a child on a swing Pendulum of the clock.

1). Write whether True or False:

a). Invention of the wheel made a great change in modes of transport.

True.

b). The result of a measurement is expressed in two parts.

True.

c). The length of the foot used is the same in all the parts of the world.

False.

d). People measured a “cubit” of cloth by the distance between the end of the outstretched arm and their chin.

False.

e). in 1790, the Americans created a standard unit of measurement called the metric system.

False.

f). The SI unit of length is a kilometer.

False.

g). For measuring large distances, metre is not a convenient unit.

True.

h). 1 km = 1000 m.

true.

i). 1 m = 100 mm.

false.

j). Correct position of the eye is also important for taking measurements.

True.

k). In rectilinear motion an object moves such that its distance from a fixed

point remains the same.

False.

2). Fill in the blanks.

i). Invention of the wheel made a great change in modes of transport.

ii). Animals were used to pull the carts that moved on wheels.

iii). The invention of the steam engine led to the development of new means of transport.

iv). A cubit as the length from the elbow to the fingertips was used in ancient Egypt.

v). Each metre (m) is divided into 100 equal divisions, called centimetre (cm).

vi). We can use a thread to measure the length of a curved line.

vi). In circular motion an object moves such that its distance from a fixed

point remains the same.

i). What caused a great change in modes of transport.

The invention of the wheel made a great change in modes of transport.

ii). What is measurement?

Measurement means the comparison of an unknown quantity with some quantity.

iii). What are the common units of measurement in ancient times?

In ancient times, the length of a foot, the width of a finger, and the distance

of a step were commonly used as different units of measurements.

iv). What is a cubit?

A cubit as the length from the elbow to the fingertips was used in ancient Egypt and was also accepted as a unit of length in other parts of the world.

v). Write in short about the different units of measurement in the ancient days.

i). A cubit as the length from the elbow to the fingertips was used in ancient Egypt and was also accepted as a unit of length in other parts of the world.

ii). People also used the “foot’ as a unit of length in different parts of the world.         iii). People measured a “yard” of cloth by the distance between the end of the outstretched arm and their chin.

iv). Romans measured with their pace or steps.

v). In ancient India, small length measurements used were an angul (finger) or a mutthi (fist).

vi). In which year metric system has started?

1790.

For the sake of uniformity, scientists all over the world have accepted a set of standard units of measurement. The system of units now used is known as the International System of Units (SI units).

viii). What is the SI unit of length?

The SI unit of length is metre.

ix). What is rectilinear motion?

The motion of an object along a straight line is called rectilinear motion.

x). give some examples of rectilinear motion?

The motion of a vehicle on a straight road, march-past of soldiers in a parade, the falling of a stone, Sprinters in a 100-metre race also move along a straight track.

xi). What is a periodic motion?

Some objects repeat its motion after some time. This type of motion is called periodic motion.

xii). Give some examples of periodic motion?

Pendulum, a branch of a tree moving to and fro, motion of a child on a swing, strings of a guitar, or the membrane of drums (tabla) being played, are all examples of periodic motion.

xiii). Define motion?

Motion is a change in the position of an object with time.

Give reason:

i). The people of the Indus valley civilisation have very good measurements of length.

The people of the Indus valley civilisation must have used very good measurements of length because we see evidence in excavations of perfectly

geometrical constructions.

Match the following:

Column  A                                     Column B

1). Cubit  –                 a). finger the length from the elbow to the finger tips

2). Yard-                    b). finger

3). Angul  –               c). fist

4). a mutthi –            d). the distance between the end of the outstretched arm and

their chin.

Column  A                                     Column B

1). Cubit  – the length from the elbow to the finger tips

2). Yard–   the distance between the end of the outstretched arm and their

chin.

3). Angul  –  finger

4). a mutthi –  fist

Match the following:

Column  A                                     Column B

1). Periodic motion  –                 a). the falling of a stone

2). Circular motion-                  b). sewing machine

3). Rectilinear motion  –            c). strings of a guitar

4). Complex motion –                d). electric fan

1). Periodic motion  –   strings of a guitar

2). Circular motion–   electric fan

3). Rectilinear motion  –  the falling of a stone

4). Complex motion –    sewing machine

16). Garbage In Garbage Out

15). Air Around Us

14). Water

13). Fun with Magnets

12). Electricity and Circuits

10). Motion and the Measurement of Distances

9). The Living Organisms – Characteristics and Habitats

8). Body Movements

7). Getting to Know Plants

6). Changes Around Us

5). Separation of Substances

4). Sorting Materials into Groups

3). Fibre to Fabric

2). Components of Food

1). Food: Where Does It Come From?

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