CLASS 9 / LAB ACTIVITY 3

EXPERIMENT - 3

AIM

To observe and compare the pressure exerted by a solid iron cuboid on sand while resting on its three different faces and to calculate the pressure exerted in the three cases.

THEORY

Simply stated, weight is the force acting vertically downward. The weight of an object is the force with which it is attracted towards the earth, that is:

For an object in free fall, when gravity is the only force acting on it, the expression for weight follows Newton's Second Law.

W = F, thus:

Here ‘g’ is the Earth's gravitational field strength, equal to about 9.81 m s−2.

An object's weight depends on its environment, while its mass does not. The SI unit of weight is the same as that of force, that is, Newton (N).The force acting on an object perpendicular to the surface is called thrust. The effect of thrust depends on the area on which it acts. Thus:

The thrust on unit area is called pressure. Thus:

      

SI unit of pressure is N/m2 or Nm-2 (Newton per square metre).

In honour of scientistBlaise Pascal, the SI unit of pressure is called pascal, denoted by Pa.

MATERIAL REQUIRED

Sand tub, brick, scale

PROCEDURE

Fill ¾ ths of a tray with dry sand and level it.

• Measure the dimensions of a solid iron cuboid accurately using a scale. Mark the three faces of the cuboid as A, B and C.
• Place the solid iron cuboid by the surface A on the plane levelled sand in the tray.
• After a few minutes, remove the Iron cuboid and you will see that it has made a depression in the sand. 
• Measure the depth (depression) it has made in the sand using the scale. 
• Repeat the same procedure for the other two surfaces.  

OBSERVATIONS

Gravitational force on the environment = …….. 

1. Calculate the area occupied by each surface of the solid iron cuboid. 

• • Area occupied by surface A in the sand = .............
  • Area occupied by surface B in the sand = ............. 
  • Area occupied by surface C in the sand = ............. 

2. Calculate the pressure made by each surface of the solid iron cuboid. 
   • Pressure made by the surface A in the sand = ............. N
   • Pressure made by the surface B in the sand = ............. N
   • Pressure made by the surface C in the sand = ............. N

3. Calculate the Depression.

3. • Depression made by the surface A in the sand = ............. cm
   • Depression made by the surface B in the sand = ............. cm
   • Depression made by the surface C in the sand = ............. cm

RESULT

PRESSURE EXERTED BY THREE DIFFERENT SURFACES IS DIFFERENT ALTHOUGH THE WEIGHT IS SAME.

PRECAUTIONS

1. Dried sand must be used.
2. The tray must have significant length and width.
3. Appropriate cuboid of dimension must be used.  

ANIMATION

https://www.youtube.com/watch?v=uRMPT5oQa_4

CLASS 9 / LAB ACTIVITY - 2

EXPERIMENT - 2

AIM

To study the Third Law of Motion using two spring balances. 

THEORY

Newton’s Third Law of Motion states: ‘To every action there is an equal and opposite reaction’. 

It must be remembered that action and reaction always act on different objects. The Third Law of Motion indicates that when one object exerts a force on another object, the second object instantaneously exerts a force back on the first object. These two forces are always equal in magnitude, but opposite in direction. 

These forces act on different objects and so they do not cancel each other. Thus, Newton’s Third Law of Motion describes the relationship between the forces of interaction between two objects.  

Whenever two bodies interact with each other, the force exerted by the first body on the second is called action. The force exerted by the second body on the first body is called reaction. The action and reaction are equal and opposite. 

For example, when we placed a wooden block on the ground, this block exerts a force equal to its weight, W = mg acting downwards to the ground. This is the action force. The ground exerts an equal and opposite force W’ = mg on the block in the upward direction. This is the reaction force.

MATERIAL REQUIRED

Two spring balances, hook

PROCEDURE

1. Take two similar spring balances of different ranges, say A and B.
2. Note the least count of the spring balances.
3. Attach the ring of spring balance A on a hook fixed in the wall and the spring balance B is attached to the hook of spring balance A.
4. Hold the spring balances exactly horizontal to the table.
5.  Pull the ring of spring balance B gently.
6. Observe and note the reading of both the spring balances.Repeat the experiment by applying different forces.

OBSERVATIONS

1. Least count of the spring balance = value of 1 small division
2. Least count of the spring balance A=………N
3. Least count of the spring balance B =…………………N

No. of observations	Reading of  B (Second spring balance) when force applied (N)	Reading of  A (First spring balance) when force applied (N)	Difference in reading of A and B (N)

RESULT

The readings on both the balances are the same in each case. Thus action and reaction forces are equal and opposite and act on two different bodies.

PRECAUTIONS

1. Spring balance of different least count should be taken.
2. The spring balance should be brought in elastic mode before doing the experiment.
3. The second spring balance should not be pulled beyond its elastic limit.
4. The reading of the spring balance should be taken without any parallax error.

ANIMATION

https://www.youtube.com/watch?v=BlgPnnwUNOQ

CLASS 9 / LAB ACTIVITY - 1

EXPERIMENT - 1

AIM
To establish relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance.

THEORY

According to Newton’s Second Law of Motion, the force acting on a body is directly proportional to the product of the mass of the body and the acceleration produced in the body by the application of the force. The acceleration takes place in the direction in which the force acts.

Newton’s Second Law of Motion precisely explains the relationship between force and acceleration.

Suppose a body of mass ‘m’ is moving by the application of a force ‘F’,  then the produced acceleration ‘a’ will be directly proportional to the applied force.

Acceleration ∝ Force 

F ∝ a 

 F ∝ m 

             Therefore, F = kma       ………… (1)

 Where k is constant of proportionality

 In SI unit, k =1

Therefore, F = ma

Importance of the Newton’s Second Law of Motion

•  Newton’s Second Law of Motion gives a quantitative measure of force.

                          F = ma

• The Second Law is a basic law of motion because both First and Third Law can be derived from this law.

MATERIAL REQUIRED

Wooden block and spring balance

PROCEDURE

1. A wooden block with a hook is placed on a table.
2. Note down the least count of the spring balance.
3. The spring balance is attached to the hook.
4. Hold the spring in such a way that the reading displayed in the spring balance can be noted down.
5. The applied force on the spring balance is gradually increased until it just starts to move.
6. The reading of the spring balance is noted.

OBSERVATION

Least count of the spring balance = value of 1 small division = …….g.wt

Trial No;	Mass of the block, M (kg)	Force required, F (N)

RESULT

Force applied to just move the block is directly proportional to the mass of the block.

ie, F ∝ M

PRECAUTIONS

1. A suitable spring balance to pull the block must be used.
2. The spring balance should be brought in elastic mode before doing the experiment.
3. The reading of the spring balance should be taken without any parallax error.
4. A smooth table or surface must be used.

      ANIMATIONS
https://www.youtube.com/watch?time_continue=71&v=1srdDxmWe34

CLASS 10 / PRACTICE WORKSHEET / ELECTRICITY

CLASS 10 / PRACTICE WORKSHEET / LIGHT AND REFLECTION

CLASS 9 / REVISION WORKSHEET / MOTION

 ARMY PUBLIC SCHOOL, GOLCONDA

CLASS - 9

REVISION WORKSHEET / MOTION

CLASS 9 / REVISION WORKSHEET / FORCES AND LAWS OF MOTION

 ARMY PUBLIC SCHOOL, GOLCONDA

CLASS - 9

REVISION WORKSHEET / FORCES AND LAWS OF MOTION

CLASS – 9/ REVISION WORKSHEET / GRAVITATION

 ARMY PUBLIC SCHOOL, GOLCONDA

CLASS - 9

REVISION WORKSHEET / GRAVITATION

CLASS – 7/ REVISION WORKSHEET / FRACTIONS AND DECIMALS

ARMY PUBLIC SCHOOL, GOLCONDA

CLASS – 7

REVISION WORKSHEET / FRACTIONS AND DECIMALS

CLASS – 7/ REVISION WORKSHEET / TRIANGLES

               ARMY PUBLIC SCHOOL, GOLCONDA

CLASS – 7

REVISION WORKSHEET / TRIANGLES

CLASS -7 / REVISION WORKSHEET / LINES AND ANGLES

ARMY PUBLIC SCHOOL, GOLCONDA

CLASS – 7

REVISION WORKSHEET / LINES AND ANGLES

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CLASS -7 / REVISION WORKSHEET / SYMMETRY

                ARMY PUBLIC SCHOOL, GOLCONDA

CLASS – 7

REVISION WORKSHEET / SYMMETRY

CLASS 7 HALF YEARLY EXAMINATION SYLLABUS

ARMY PUBLIC SCHOOL, GOLCONDA

SYLLABUS (HALF YEARLY EXAMINATION) 2018-2019

CLASS – VII

SUBJECT: ENGLISH

v Literature section

·        The three questions

The squirrel

·        A gift of chappals

The rebel

·        Gopal and the Hilsa fish

The shed

·        The ashes that made trees bloom

Chivvy

·        Quality

Trees

v Supplementary reader

·        Tiny teacher

·        Bringing upkari

·        The desert

·        The cop and the anthem

·        Golu grows a nose.

v Writing section

·        Message, Letter, Storywriting.

v Grammar

·        Chapter – 1 to 11

Sentences, nouns, adjectives and degrees of comparison, pronouns, articles and determiners, verbs, non-finite verbs, phrase, clauses, sentences – simple/ compound/ complex, modals.

v Reading section

·        2 Unseen passage

  

SUBJECT: HINDI

v  वसंत , पाठ – 1, 2, 3, 5 – प्रश्नोतर

          पाठ – 1, 2, 3, 5, 11, 13 – शब्दार्थ 

v कवि परिच्य 

v व्याकरण -   संज्ञा, सर्वनाम, विशेषण, क्रिया, क्रिया-विशेषण, विलोम, लिंग, वचन, अपठित गद्यांश, पयार्यवाची , पत्र, अनुछेद

 SUBJECT: MATHS

v chapter -1; Integers

v chapter -2; Fractions and decimals

v chapter -3; Data Handling

v chapter -5; Lines and angles

v chapter -6; Triangle and its properties

v chapter -13; exponents and Power

v chapter -14; Symmetry

SUBJECT: SCIENCE

v Lesson – 1; Nutrition in plants

v Lesson – 2; Nutrition in animals

v Lesson – 4; Heat

v Lesson – 5; Acid, bases and salts

v Lesson – 6 ;Physical and chemical changes

v Lesson – 10; Respiration in organisms

v Lesson – 13; Motion and time

SUBJECT: SOCIAL STUDIES

v History   

·        Lesson -1 ; Tracing changes through thousand years

·        Lesson -2 ; New kings and kingdoms

·        Lesson -3 ; The Delhi sultans

v Geography

·        Lesson -2 ; Inside our earth

·        Lesson -3 ; Our changing earth

·        Lesson -4 ; Air

v Civics

·        Lesson -2 ;  Role of the government in health

·        Lesson -3 ; How the state government works

·        Lesson -4 ; Growing up as boys and girls

SUBJECT: SANSKRIT

पाठः

v 1- सुभाषितानि

v 2- दुर्बुद्धिःविनश्यति

v 3- स्वावलम्बनम्

v 4- हास्यबालकविसम्मेलनम्

v 5- पण्डिता रमाबाई

v 6- सदाचारः

व्याकरणः

वाक्यरचना, अव्ययः, संख्यावाचक शब्दाः, विलोमपद, समानार्थक शब्दाः, धातुरूपम्- लृट्लकार (पठिष्यति)