Motion And Measurement Of Earth - Class 6 Physics - Extra Questions

In which of the following examples of motion, can the body be considered approximately a point object:
(a) A railway carriage moving without jerks between two stations.
(b) A monkey sitting on top of a man cycling smoothly on a circular track.
(c) A spinning cricket ball that turns sharply on hitting the ground.
(d) A tumbling beaker that has slipped off the edge of a table.

(a) The size of a carriage is very small as compared to the distance between two stations. Therefore, the carriage can be treated as a point sized object.

(b) The size of a monkey is very small as compared to the size of a circular track. Therefore, the monkey can be considered as a point sized object on the track.

(c) The size of a spinning cricket ball is comparable to the distance through which it turns sharply on hitting the ground. Hence, the cricket ball cannot be considered as a point object.

(d) The size of a beaker is comparable to the height of the table from which it slipped. Hence, the beaker cannot be considered as a point object.


Name five objects which can be made from wood.

Five objects that can be made from wood are:-
(i) Houses, (ii) Furnitures, (iii) Paper, (iv) Pencil and (v) Doors.


Metre scale is used to measure _______

A metre scale is used to measure length of an object which has SI unit of meter $$m$$.


If the position of an object does not change with time, it is said to be at ______.

rest


An object is said to be at _________ (rest/motion), if it changes its position with respect to its surroundings in a given time

Motion


When is a body said to be in motion?

A body is referred to be in a state of motion when there are changes in the position of the body with respect to its immediate surroundings.


What is absolute rest ?

Absolute rest refers to a now-discarded idea that there does exist a special inertial frame, which is "really" at rest, and with respect to which all other motion should be measured.


Define rest and motion

The objects which do not change their positions with time are said to be at rest. The objects which change their positions with time are said to be in motion.


Two examples of periodic motion

The two examples of the periodic motions are:
  1. Motion of pendulum clock
  2. Motion of a swing


Differentiate between Rectilinear motion and Curvilinear motion.

When an object moves along a straight line its motion is called 
Rectilinear motion but when the object moves along a curved path its 
motion is called Curvilinear motion


Name the SI unit of mass.

The SI unit of mass is the kilogram $$(kg)$$


The least value measured with meter-scale is (if the meter scale is divided into 1000)

Total length of scale$$(L)$$-
$$L = 1\ m$$
Total no of divisions$$(n)$$-
$$n = 1000$$
So least value will be equal to the value of one division.
Value of one dividion$$(LV)$$-
$$LV = \dfrac{L}{n}$$
$$\Rightarrow LV = \dfrac{1}{1000}\ m$$
$$\Rightarrow LV = 0.001\ m$$
$$\Rightarrow LV = 1\ mm$$
Hence, least value is one millimeter.


Why can hand spam or arm length not be used as standard units of length?

Hand span and cubit are not used as standard units of length because their sizes vary from person to person. So, two different persons may give different measurements for the same length, which is not desirable for a standard unit.


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

The length of pace or a footsteps various from person to person. If the length of foot- steps will be the used as standard unit for measurement of length then two measured quantity will not be same, Hence footsteps or pace is not a constant quantity and cannot be used as a standard unit of length.


Give the unit for measuring the following :
(a) Distance between Delhi and Jaipur.
(b) Thickness of a coin.
(c) Length of your eraser.
(d) Length of your shoe lace.

(a) Kilometer
(b) Millimeter
(c) Centimeter
(d) Centimeter


State two precautions to be observed while measuring length with the help of a meter scale.

Two precautions are :
(i) The initial point of distance must coincide with the zero reading of meter scale.
(ii) The eye should be kept in line with the point of measurement.


Give one example of each of the following types of motion :
(a) Linear (b) Translation (c) Circular (d) Periodic

Types of motionExample
(a) LinearA motion of stone falling
(b) TranslatoryBuses
(c) CircularCeiling fan
(d) PeriodicPendulum of clock


Define the term standard unit.

The unit that could be used everywhere as a basic unit of measurement is called a standard unit.


Why do we need standard unit measurement?

We need standard unit for measurement to make our judgement more reliable and accurate. For proper dealing, measurement should be same for everybody. Thus there should be uniformity in measurement. For the sake of uniformity we need a common set of units of measurement, which are called standard units. Nowadays Si units in science and technology almost accepted universally.


Can an object possess translatory and rotatory motion at the same time? Give an example.

Yes, an object can possess translatory and rotatory motion at the same time.
For example : When a wheel moves at the plane surface, it exhibits translation as well as rotational motion at the same time.


Fill in the blanks with the correct words:
The distance of an object from one end to the other is called ____ (length/kilometer)

The distance of an object from one end to the other is called its Length.
Kilometer is the unit of length.


State the requirements of a good unit.

Four requirements of a good unit are given as follows:

1) A good unit should be correct. The basic requirement of the unit is to measure the correct parameter of different physical quantities. Thus, it should be correct.

2). A good unit should be clear, precise and simple.

3) A good unit should be testable because all the physical concepts are based on experiments.

4). a good unit should be feasible and practically available.



Give reasons
All masses cannot be measured in Kilogram.

We cannot measure all masses in kg, because there are very small quantities like $$1 gm$$ nd even smaller, and this will not be an accurate measurement in Kg


A moving carrom board coin describes a ___________ motion.

A moving carrom board coin describes a linear motion as it moves in a straight line.


The diagram below in fig . 8.15 shows the reading on the dials of a meter. State what is its reading. 
1358261_d36b768cb7a14e11b8460318aae199b0.png

The reading are : $$ a.2 \quad b.7 \quad c.8 \quad d.9 $$


What is translatory motion?

As given in figure Translatory motion is the type of motion in which all points of a moving body move uniformly in the same line or direction. 
1280102_1378742_ans_749090c116174382acaec402eab89dd4.jpg


Give one example each of uniform and non uniform type of motion in our daily life.

Uniform motion: When a car is moving at a constant velocity of $$50 \, Km/hr$$ in a straight line, the car is covering equal distances in equal intervals of time irrespective of the length of time. Then we can say that the car is uniform motion.
Non-Uniform motion: When a race car constantly accelerates to win the race, then the car travels unequal distances in equal intervals of time. Hence such an instance can be referred to as an example of non-uniform motion.
Uniform circular motion: When a table fan rotates at a constant speed then it can be described as a uniform circular motion as it is rotating in a circle in which at all instances change of direction is taking place and movement is also circular.
Non-uniform circular motion: Motion of a table fan when it switched off till its stops, can be referred as an example of non-uniform circular motion as the rotation of the fan is not constant and it is changing with time.
Uniformly accelerated Motion: When a body falls freely, then it accelerates uniformly with a magnitude of the acceleration due to gravity. Thus the velocity of the body increases by equal amounts in equal intervals of time. Hence it can be referred to as an example of uniformly accelerated motion.
Non-uniformly accelerated motion: When a feather falls down in heavy storm, then the velocity of the feather decreases sometimes and sometimes it increases in unequal amounts in equal intervals of time. Thus it can be referred to as an example of non-uniformly accelerated motion.


Define motion.

The change in position of a body with time when compared with that of another body is called motion.


Fill in the blanks.
The SI unit of length is ________.

The SI unit of length is metre.


Fill in the blanks-
In rectilinear motion, object moves _______ a line.

along straight.


Write one example for each of the following type of motion.
(i) Rectilinear
(ii) Circular
(iii) Periodic
(iv) Circular and periodic.

Motions with example
(i) Rectilinear motion - A car moving in straight line.
(ii) Circular motion - Moving blades of a fan.
(iii) Periodic motion - The motion of a swing.
(iv) Circular and periodic - Tip of minute hand of clock.


Fill in the blanks-
Motion of an object or a part of it around a fixed point is known as _______ motion.

Circular.


Correct the following:
The motion of a swing is an example of rectilinear motion.

No, the motion of swing is not a rectilinear motion but a periodic motion because the swing repeats its motion after a certain time period.


Match the following columns

 
List I
List II 
 
A. Length of a housing plot
 4. Measuring tape
 
B. The breadth of a book
 6. Meter ruler
 
C. Mass of an apple
2. Beam balance 
 
D. Period of time of a body
 1. Clock
 
E. The temperature of a body
 3. Thermometer
 
F. The surface area of a leaf
 5. Graph paper


Explain with an example how you will use the metre ruler, if the ends of ruler are broken.

The ends of the ruler get damaged with use and its zero may not be visible. To measure the length of an object with such a ruler, the object is placed close to a specific markings on the ruler and positions of both ends of the object are read on the ruler. 
The difference of the two readings gives the length of the object. In fig, the reading on ruler at the end X is $$1.0 \,cm$$ and at the end Y is $$4.3 \,cm.$$ So the length of the rod XY is $$4.3 - 1.0 = 3.3 \,cm.$$
1675725_1798518_ans_30bc264aed634988a68657b089de2966.png


Fill in the blanks-
A body repeating its motion after certain interval of time is in _____ motion.

 Periodic.


Name the device which you will use to measure the perimeter of your play ground. Describe in steps how you will use it.

We will use a measuring tape to measure the perimeter of our playground. 
To measure the length of playground the tape is spread along the length of the curved area.


Examples of motion : Hands of an athlete in a race.
Type/types of motion : ............

Hands of an athlete in a race - Oscillatory motion


Which is the correct position of the eye. Write the correct length of the stick.
1798525_7c5c83c6e39b4694b27380c43f0b3b90.png


To look at current measurements, 'B' is the correct position of the eye. Correct length of the stick $$PQ = 3.2 \,cm$$


Examples of motion : 
The movement of our chest while breathing.
Type/types of motion : ............

This is an example of oscillatory motion where our chest continuously moves up and down, so we can say this is an oscillatory motion.


The motion in a ________ is rectilinear motion.

 Answer: Straight line

Explanation


The motion in a straight line is rectilinear motion as the direction of motion is not changing with time .




Examples of motion : Soldiers in a march on a straight road.
Type/types of motion : ............

Soldiers marching on a straight road is an example of Rectilinear motion


The diagram above shows a stick placed along a metre RULER. The length of the stick is measured keeping the eye at positions A, B and C.
Write the length if stick PQ as observed, for each position of the eye. Are they all same ?

(a) Write the length of stick PQ as observed,  for each position of the eye.  Are they all the same?

(b) Which is the correct position of the eye ? Write the correct length of the stick.



1798524_1bc08942f90349b785d4d51467cbb37c.PNG

When taking readings from any scales for measuring the length of any object. The observer must look perpendicular to the scale. If the observer looks at an angle then the reading he sees will be incorrect. 
The correct length of PQ is $$3.2cm$$ observed from position B. 
They are all not same. Readings from positions A and C are incorrect. 
From $$C$$ it is $$3.00cm$$
From $$A$$ it is $$3.4cm$$


Examples of motion : Pedal of a bicycle in motion.
Type/types of motion : ............

Pedal of a bicycle in motion - Circular motion


Examples of motion : Motion of a spining wheel.
Type/types of motion : ............

The motion of a spinning wheel is an example of $$rotatory$$ motion.


Examples of motion : A plucked string of a sitar.
Type/types of motion : ............

A plucked string of a sitar shows a oscillatory motion.


Examples of motion : The movement of the wheel of a bicycle.
Type/types of motion : ............

The motion of the wheel of a bicycle is a combination of translational and rotational motion. 
It exhibits rotational motion as it rotates about its own axis. At the same time, it advances forward. So it has a translational motion too.


A car moving on a straight road.
Type/types of motion : ............

Rectilinear motion.
Linear motion, also called rectilinear motion, is one-dimensional motion along a straight line, and can therefore be described mathematically using only one spatial dimension.


When a body is said to be at rest?

A body is referred to be in a state of rest and stationary when there is no change in the position of the body with regards to its immediate surroundings.
For example:A tree on the ground is at rest as it's position is not changing with respect to time.


Examples of motion : A stone falling from a certain height.
Type/types of motion : ............

Rectilinear motion


Examples of motion : Motion of a swing.
Type/types of motion : ............

Motion of swing : Oscillatory motion


What do you mean by motion in one direction?

Motion in one direction with reference to a body is when the body moves in a straight line path only.


Type of the motion in the below statement:
The motion of a train on a straight bridge.

The given bridge is straight so the motion of the train on the bridge is rectilinear motion. This is called one dimension motion of an object where the direction of the object remains the same through the motion.


State whether the given statement is correct or incorrect.
$$\text{Distances between two cities is measured in kilometers}$$.

$$\textbf{Correct}$$
Distance between cities or 2 locations is measured in either kilometer, or miles, or nautical miles.


Classify the following as motion along a straight line, circular or oscillatory motion:
Motion of a horse pulling a cart on a straight road.

Motion of a horse pulling a cart on a straight road – Straight line motion. As the horse cart is moving on a straight road. Therefore motion is along the straight line


Classify the following as motion along a straight line, circular or oscillatory motion:
Motion of a child on a see-saw.

Motion of a child in a sea saw is an $$\textbf{oscillatory}$$ motion.
This is because the child goes up and down at a continuous speed at a particular point of time. Constant up and down movement is generally regarded as the oscillation and hence the motion of a child is generally regarded as the oscillatory motion


What does the path of an object look like when it is in uniform motion?

When the object is in uniform motion, it covers equal distance at equal intervals of time.


Fill in the blanks:
Motion of wheel of a bicycle is _________

Motion of wheel of a bicycle is $$\underline{Circular \ motion.}$$ 

If we mark a point anywhere on the wheel of the bicycle, the distance of this point from the centre of the wheel, will remain the same as it rotates. This type of motion is called circular motion.


Classify the following as motion along a straight line, circular or oscillatory motion:
Motion of your hands while running.

Motion of your hands while running – $$\textbf{Oscillatory}$$ motion. During running the hands move to and fro and as this motion gets repeated after certain time interval. Therefore it is oscillatory motion.


Classify the following as motion along a straight line, circular or oscillatory motion:
Motion of a child in a merry-go-round.

The motion of the merry-go-round is circular. Therefore kids sitting inside it experiences the circular motion.


Give two examples of the following 
Oscillatory motion

The two examples of the Oscillatory motion are:
  • Pendulum of clock
  • Motion of a child on a swing


Give two examples of linear motion.

Examples of linear motion-
Falling of stone from a certain height.
An athlete running $$200\ m$$ on a straight track.
Train running in a straight track.
Car moving at a constant speed.


How many centimeters are there in $$1\,m$$ ? 

There are $$100\,cm$$ in 1 m.


Give an example for circular motion.

The motion of the arms of a circular watch is an example of circular motion.


Give two examples for each of the following 
Spinning motion

The two examples of the Spinning motion are:
  • Rotating fan
  • Wheel of sewing machine


Give two examples of Periodic motion

The two examples of the Periodic motion are:
  • Pendulum of clock
  • Motion of a heart beat


Give two examples of the following :
Circular motion.

Two examples of the Circular motion are:
  • The motion of the blades of a fan
  • The motion of a planet around the sun


Give two examples of the following -
Random motion

The two examples of random motion are: 
  • Motion of a football player 
  • Movement of a mosquito


Using following objects how can you measure the diameter of a ball?
ball, two wooden blocks, metre scale

The ball is kept in between two wooden blocks as shown in this figure whose diameter is to be measured.
1782768_1850621_ans_1ec9566e984c4430943c0f7f264c0434.png


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

Modes of Transport 
(i) Land - Bus, truck, train.
(ii) Water - Ship, boat.
(iii) Air - Aeroplane, Helicopter


Identify the different types of motion in the following word diagram given as Fig.
1788166_7b9d45503f8946e38a6205871317f310.png

-
1636303_1788166_ans_a2eb68c7d7df40338d0821c76dda9c2f.png


What type of motion do the following objects have?
(a) A galloping of a horse.
(b) The needle of a sewing machine.
(c) A flying mosquito.
(d) The blades of an electric fan.
(e) The wheels of moving car.

(a) The galloping of a horse : Linear  motion.
(b) The needle of a sewing machine : Periodic  motion.
(c) The movements of mosquito : Random  motion.
(d) The blades of an electric fan : Circular  motion.
(e) Wheels of moving car : Linear motion and Rotational motion.


How are the motions of a wheel of a moving bicycle and a mark on the blade of a moving electric fan different?
Explain.

Wheels of a moving bicycle show rectilinear motion and circular motion. Because when the wheel is rotating, it also moves the bicycle forward (unless breaks are applied). A blades of moving fan only show circular motion, as it doesn't make the fan move from place to place. It is at a fixed position.


Name five different types of motion you know.

Different types of motion

Some of the different types of motion are as follows:

  •  Translatory motion: A motion in which all the points of the object move through the same distance in equal intervals of time is called translatory motion

  •  Rotatory motion: A body is said to be in rotatory motion if it moves about the fixed axis.

  • Periodic motion: Any motion which gets repeated after regular intervals of time is called a periodic motion.

  •  Oscillatory motion: The to and fro motion of a body about a fixed point is called oscillatory motion.It is a type of periodic motion.

  •  Vibratory motion: It is a motion in which some part of the body always remains fixed and the rest part moves to and fro about its mean position.




Boojho was riding in his bicycle along a straight road. He classified the motion of various parts of the bicycle as
(i) Rectilinear motion
(ii) Circular motion and
(iii) Both rectilinear as well as circular motion.
Can you list one part of the bicycle for each type of motion? Support your answer with reason.

S.No.Type of MotionPart of bicycleReason
$$1.$$RectilinearHandlesThe handles do not move in circular or rotatory motion.
$$2.$$CircularPedalsThe pedals are fixed to the chain and cannot move in any other direction except circular.
$$3.$$Both rectilinear and circularWheelsWheels of a moving bicycle show rectilinear motion and circular motion. Because when the wheel is rotating, it also moves the bicycle forward.


Explain the meaning of rectilinear motion .

Rectilinear motion : If the motion of a body is along a straight line, it is said to be the rectilinear or linear motion. Example : The motion of bullet fired from a gun.


Four children measure the length of a table which was about $$2\ m$$. Each of them used different ways to measure it.
(i) Sam measured it with a half metre long thread.
(ii) Gurmeet measured it with a $$15\ cm$$ scale from her geometry box.
(iii) Reena measured it using her hand span.
(iv) Salim measured it using a $$5\ m$$ long measuring tape.
Which one of them would get the most accurate length?
Give reason for your answer.

The correct answer is option (iv). The most accurate measurement will be done by Saleem as he used a standard instrument to measure the table that is a $$5m$$ measuring tape, which made easy for him to measure the table in one go.


Explain the meanings of curvilinear motion. Give one example

Part 1: Explaining Curvilinear motion


Curvilinear motion - If the motion of a body is along a curved path, it is known as curvilinear motion. 

The direction of motion is constantly changing in this motion.


Part 2: Example of curvilinear motion

The motion of a car while taking a turn on the road, a bike moving on a circular race track, roller skating on a curved track are all examples of Curvilinear motion. 




What do you mean by translatory motion? Give one example.

Part 1: Definition of translatory motion


A motion in which all the points of the object move through the same distance in equal intervals of time is called translatory motion.


Part 2: Example  

Motion of a person walking on a road is an example of translatory motion.




Match the events related to motion in Column I with the types of motions given in Column II

The correct match is-
Column IColumn II
a) A moving swing.(i) Periodic motion
b) A movement of tip of the minute hand of a clock in one hour.(iii) Circular motion.
c) A moving wheel of a sewing machine.(ii) Rotational motion.


Fill in the blanks using one of the words : at rest, in motion.
A person sitting in a compartment of a moving train is________ relative to the other person sitting by his side is _________relative to the platform.

Correct answer: A person sitting in a compartment of a moving train is at rest relative to the other person sitting by his side and is in motion relative to the platform.

Explanation


  • Since the position of the person is not changing relative to the other person with time in the compartment, the man is at rest relative to the other person.

  • However, since the train is moving, the position of the person is changing relative to the platform.So, the man is in motion relative to the platform.




Name the type/types of motion being performed by the following:
Vehicle on a straight road

Rectilinear motion

Solution:


Since, the vehicle is moving on a straight road, it is following a straight line path.

Therefore, its motion is Rectilinear motion.




How does a rotatory motion differ from the circular motion?



Rotatory motion

Circular motion

A body is said to be in rotatory motion if it moves about the fixed axis.


The motion of a body along a circular path is known as circular motion.

The axis of rotation passes from a point in the body itself. 

The axis of revolution doesn’t pass through the body or we can say it passes through the point outside the body.

The body undergoes rotation.

The body undergoes revolution

Ex.- Motion of earth about its own axis is an example of rotatory motion

Ex.- Motion of earth around the sun is an example of circular motion.



What is random motion. Give one example.

Part 1: Definition of random motion


Random motion - The motion of a particle having no specific path and having unexpected shifts in its motion are known as Random motion.

Random motion can not be predicted.


Part 2: Examples of random motion

The motion of a mosquito is the most common example of a random motion.

It does not have a fixed trajectory motion and changes its path unexpectedly.




Name the type/types of motion being performed by each of the following:
Pendulum of a wall clock

Oscillatory motion, Periodic motion

Solution: 


Pendulum of a wall clock undergoes oscillatory motion as it oscillates about its mean position.

This is also a periodic motion




Name the type/types of motion being performed by each of the following:
Smoke particles from chimney

 Non periodic or Random motion, 

Solution : 

Smoke from a chimney has no fixed direction of motion, hence it is an example of Random motion. 

Also since the motion doesn’t repeat itself it is non periodic.




What is meant by circular motion ? Give one example.

Part 1: Definition of circular motion

The motion of a body along a circular path is known as circular motion.

The direction of motion is constantly changing in circular motion.


Part 2: Example of circular motion

When a person whirls a stone tied by a string, the motion of the stone is an example of circular motion.




Name the type/types of motion being performed by each of the following:
A spinning top.

Rotatory motion

Solution:

A spinning top rotates about an axis passing through itself.

So it is an example of rotatory motion.






Name the type/types of motion being performed by the following:
Earth around the Sun

 Circular motion, rotatory motion, periodic motion

Solution:

Earth moving around the sun rotates on its own axis as well as revolves around the sun.

So, the motion is both circular as well rotatory motion.

Since, the motion of earth repeats after some time it is also a periodic motion.




Name the type/types of motion being performed by each of the following:
Hands of a clock

Circular motion, Periodic motion

Solution: 

Since any point on the hand of the clock  moves in a circular direction, they are said to be in circular motion. It is also periodic as it repeats its motion .




State the types of motion of the following :
The wheel of a bicycle

Answer: Mixed = Rotatory and translational motion

Explanation

The motion of wheels of a bicycle is both translational and as well as rotational because the wheel is rotating about the axle of the wheel and the bicycle is also translating forward.Hence, it comprises more than one type of motion.



Define uniform and non uniform motion.

If the speed of an object moving along a straight line keeps changing, its motion is called non – uniform. An object moving along a straight line with a constant speed is said to be in uniform motion.


Classify the following as motion along a straight line, circular or oscillatory motion:
Motion of the hammer of an electric bell.

Motion of the hammer of an electric bell – $$\textbf{Oscillatory}$$ motion. When the hammer vibrates the bell it starts vibrating. It is an example of oscillatory motion.


State the types of motion of the following :
The carpenter's saw

Answer: Mixed = Translatory and Oscillatory motion


Explanation

The motion of saw of a carpenter is an example of mixed motion i.e. combining translational motion with the oscillatory motion.

This is because the carpenter is continuously moving the saw to and fro in a straight line, thereby causing the oscillatory motion.

Also while cutting when saw penetrates the wood it translates downward, thereby causing translational motion.




_________ were used to pull vehicles that moved on wheels.

Animals were used to pull vehicles that moved on wheels.
2117572_1951661_ans_a5d45cadb9644f7580cd267bd0c01c55.png


Class 6 Physics Extra Questions