NCERT Solutions For Class 8 Science Chapter 11 Force and Pressure

Download PDF

NCERT Solutions for Class 8 Science Chapter 11 Force and Pressure: Solved Exercise Questions

Q1. Give two examples each of situations in which you push or pull to change the state of motion of objects.

Answer:

Two examples of the situation in which the state of motion of an object is changed through a push are as follows:

(a) A table whose position in a room has to be changed is moved by pushing it.

(b) In a match of cricket, the batsman hits the ball by pushing it with a bat.

Two examples of the situation in which the state of motion of an object is changed through a pull are as follows:

(a) In a game of tug of war, both teams try to bring the rope towards their side by pulling it.

(b) A train moves when the engine pulls the rest of the bogies.

Q2. Give two examples of situations in which applied force causes a change in the shape of an object.

Answer:

Two examples of situations in which applied force causes a change in the shape of an object are as follows:

(a) The shape of a rubber band changes (it stretches) once it is pulled from both ends.

(b) The shape of dough is changed before making it into a roti.

Q3. Fill in the blanks in the following statements.

(a) To draw water from a well we have to __________ at the rope.
(b) A charged body __________ an uncharged body towards it.
(c) To move a loaded trolley we have to __________ it.
(d) The north pole of a magnet __________the north pole of another magnet.

Answer:

(a) To draw water from a well we have to pull at the rope.
(b) A charged body attracts an uncharged body towards it.
(c) To move a loaded trolley we have to either pull or push it.
(d) The north pole of a magnet repels the north pole of another magnet.

Q4. An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms.

muscular, contact, non-contact, gravity, friction, shape, attraction

(a) To stretch the bow, the archer applies a force that causes a change in its __________.
(b) The force applied by the archer to stretch the bow is an example of __________ force.
(c) The type of force responsible for a change in the state of motion of the arrow is an example of a __________ force.
(d) While the arrow moves towards its target, the forces acting on it are due to __________ and that due to __________ of air.

Answer:

a) To stretch the bow, the archer applies a force that causes a change in its shape .
(b) The force applied by the archer to stretch the bow is an example of muscular force.
(c) The type of force responsible for a change in the state of motion of the arrow is an example of a contact force.
(d) While the arrow moves towards its target, the forces acting on it are due to gravity and that due to the friction of air.

Q5. In the following situations identify the agent exerting the force and the object on which it acts. State the effect of the force in each case.

(a) Squeezing a piece of lemon between the fingers to extract its juice.

Answer:

The fingers exert muscular force on the lemon . As an effect of this force, the lemon gets squeezed .

Q6. In the following situations identify the agent exerting the force and the object on which it acts. State the effect of the force in each case.

(b) Taking out paste from a toothpaste tube.

Answer:

We use our fingers to apply muscular force on the toothpaste tube . This applied muscular force changes the shape of the tube causing the toothpaste to come out of it.

Q7. In the following situations identify the agent exerting the force and the object on which it acts. State the effect of the force in each case.

(c) A load suspended from a spring while its other end is on a hook fixed to a wall.

Answer:

The load pulls the spring . As an effect of this pull, the spring stretches .

Q8. In the following situations identify the agent exerting the force and the object on which it acts. State the effect of the force in each case.

(d) An athlete making a high jump to clear the bar at a certain height.

Answer:

The athlete pushes the ground using muscular force. This causes the athlete to rise in the air.

Q9. A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?

Answer:

While hammering a hot piece the blacksmith applies force on it using the hammer thus causing a change in the shape of the piece of iron. For example, the blacksmith can make a cylindrical block of iron to rectangular block by heating it and hammering.

Q10. An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?

Answer:

On rubbing the balloon against a piece of synthetic cloth the balloon gains charge . The wall is uncharged and is attracted by the charged balloon since a charged body attracts an uncharged body . The electrostatic force is responsible for the attraction between the balloon and the wall.

Q11. Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.

Answer:

The forces acting on the bucket are muscular force applied by our hand and gravitational force. The forces acting do not bring a change in the state of the motion as the forces are equal in magnitude and act in the opposite direction.

Q12. A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.

Answer:

Two forces acting on the rocket are the gravitational force and friction of the air in the atmosphere. The gravitational force pulls the rocket towards the earth and the friction force also opposes the motion of the rocket.

Q13. When we press the bulb of a dropper with its nozzle kept in water, air in the dropper is seen to escape in the form of bubbles. Once we release the pressure on the bulb, water gets filled in the dropper. The rise of water in the dropper is due to

(a) the pressure of water.
(b) the gravity of the earth.
(c) the shape of a rubber bulb.
(d) atmospheric pressure.

Answer:

The rise of water in the dropper is due to atmospheric pressure. The atmospheric pressure is more than the pressure inside the dropper thus pushing the water inside it.

The experts at Careers360 have created easy-to-understand class 8 science chapter 11 question answer. These solutions are available in the form of a PDF, making it convenient for students to access and utilize them. The Solution of class 8 chapter 11 science consists of a total of thirteen questions, which are a mix of straightforward question-answer and fill-in-the-blanks types. These solutions can aid students in their exam preparation and ensure that they have a clear understanding of the concepts covered in the chapter. Additionally, practising force and pressure class 8 questions answers can help students identify their strengths and weaknesses in the subject and focus on improving their performance.

NCERT Solutions For Class 8 Science- Chapter-wise

Chapter 1	Crop Production and Management
Chapter 2	Microorganisms Friend and Foe In Microorganisms
Chapter 3	Synthetic Fibres and Plastics
Chapter 4	Materials Metals and Non Metals
Chapter 5	Coal and Petroleum
Chapter 6	Combustion and Flame
Chapter 7	Conservation of Plants and Animals
Chapter 8	Cell Structure and Functions
Chapter 9	Reproduction in Animals
Chapter 10	Reaching the Age of Adolescence
Chapter 11	Force and Pressure
Chapter 12	Friction
Chapter 13	Sound
Chapter 14	Chemical Effects Of Electric Current
Chapter 15	Some Natural Phenomena
Chapter 16	Light
Chapter 17	Stars and the Solar System
Chapter 18	Pollution of Air and Water

Force and Pressure Class 8 Questions and Answers: Important Formulas and Diagrams + eBook link

Force

A force is a push or pull on an object.

1694692122887

Forces can change the state of rest or motion of an object.
The SI unit of force is the Newton (N).

Effects of Force

Forces can change the shape, size, or speed of an object.
Forces can also change the direction of motion.

Formula for calculating the force exerted by a body

Force = mass × acceleration

Pressure

Pressure is the force applied per unit area.

Pressure (P) = Force (F) / Area (A)

Where: P is in pascals (Pa), F is in Newtons (N), and A is in square meters (m²)

Archimedes' Principle

Archimedes' principle states that the buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object. This principle explains why objects float or sink in fluids.

Force And Pressure Class 8 NCERT Science Topics

Subtopics of the chapter 11 class 8 science are given below:

11.1. Force – A Push or Pull

11.2. Forces are due to an Interaction

11.3. Exploring Forces

11.4. A Force can Change the State of Motion

11.5. Force can Change the Shape of an Object

11.6. Contact Forces

11.7. Non-contact Forces

11.8. Pressure

11.9. Pressure Exerted by Liquids and Gases

11.10. Atmospheric Pressure

NCERT solutions for class 8 science chapter 11 Force and Pressure- Points to remember:

The questions explained in the NCERT solutions for class 8 science chapter 11 force and pressure are based on the following points.

Force is either a push or a pull on an object resulting from interaction with another object.
The direction of motion of an object can be changed by applying force.
Force can alter the shape of an object
Force can influence the state of motion
The pressure is the force per unit area.
The pressure exerted by the air around us is known as atmospheric pressure.
The value of atmospheric pressure is very large, but our body is not feeling it because the pressure inside the body is also equal to the atmospheric pressure and balances the pressure from outside.

There are so many interesting examples and situations that are given in the NCERT book grade eight-chapter 11. You can do all the activities given in the NCERT book and it will be a fun and a learning experience. CBSE NCERT solutions for class 8 science chapter 11 force and pressure helps students in solving homework problems also.

Key Features of Class 8 Science ch 11 Question Answer

Comprehensive Coverage: Force and pressure class 8 solutions provides comprehensive coverage of various concepts related to force and pressure. It addresses a wide range of topics, ensuring a thorough understanding of the chapter.
Real-Life Examples: Many questions in this force and pressure class 8 ncert solutions are framed using real-life examples. This approach helps students connect theoretical concepts with practical situations, making learning more engaging and relatable.
Conceptual Clarity: The class 8 science chapter 11 ncert solutions are designed to test the student's understanding of fundamental concepts related to force and pressure. They encourage students to think critically and apply their knowledge to solve problems.
Variety of Question Types: The class 8 force and pressure ncert solutions section includes a variety of question types, such as multiple-choice questions, short answer questions, long answer questions, and numerical problems. This diversity allows students to practice different problem-solving techniques.
Application-Based Questions: Some questions require students to apply their knowledge of force and pressure to real-world scenarios. This helps students see the practical implications of the concepts they are learning.
Step-by-Step Solutions: For numerical problems and complex questions, step-by-step force and pressure class 8 questions and answers are often provided. These solutions guide students through the problem-solving process, helping them understand the methodology.
Assessment and Practice: The science chapter 11 class 8 questions serve as a valuable tool for self-assessment and practice. Students can gauge their understanding of the chapter by attempting these questions and then referring to the answers to check their accuracy.
Exam-Orientation: Many questions are framed with a focus on exam preparation. By practising these ch 11 science class 8 questions, students can become better prepared for their Class 8 Science exams

NCERT Solutions For Class 8: Subject-Wise

Also Check NCERT Books and NCERT Syllabus here:

Frequently Asked Questions (FAQs)

1. Is force and pressure studied in higher classes?

Yes, force and pressure are important topics of NCERT Class 9 Syllabus. These are basic concepts in mechanics that will be studied in Class 11 Physics book

2. What is Pressure?

Pressure is defined as force per unit area. If F is the force and A is the area, then pressure P=F/A

3. What is the SI unit of force?

The SI unit of force is Newton(N)

4. What is the SI unit of Pressure?

The SI unit of pressure is Pascal(Pa)

Also Read

NCERT Solutions for Class 8 Science Chapter 11 Force and Pressure

NCERT Solutions for Class 8 Science Chapter 10 Reaching The age of adolescence

NCERT Solutions for Class 8 Science Chapter 9 Reproduction in Animals

NCERT Solutions for Class 8 Science Chapter 7 Conservation of Plants and Animals

NCERT Solutions for Class 8 Science Chapter 3 Synthetic Fibres and Plastics

NCERT Solutions for Class 8 Science Chapter 2 Microorganisms Friend and Foe

NCERT Syllabus for Class 8 2024-25 - Download All Subjects PDF

Articles

Silverzone SKGKO Answer Key 2024-25: Download Smart Kid GK Olympiad Answer Key @ silverzone.org

Nov 20, 2024

Sainik School Entrance Exam 2025: Application, Exam Date, How to Apply, Syllabus

Nov 20, 2024

ICICI Education Loan: Eligibility, Interest Rates & Application Process

Nov 19, 2024

MPSOS 10th Result 2024 - Check MPSOS Class 10 December 2024 Exam Result @mpsos.nic.in

Nov 16, 2024

List of Rashtriya Military School in India 2024-25: Best RMS Schools

Nov 16, 2024

How to Track NSP Payment Status – Step-by-Step Guide for Scholarship Updates

Nov 14, 2024

What is OTR in NSP? – Comprehensive Guide to One Time Registration

Nov 14, 2024

Best Hobbies to Mention in Resume - [Updated for 2024]

Nov 13, 2024

Upcoming School Exams

National Institute of Open Schooling 12th Examination

Admit Card Date:04 October,2024 - 29 November,2024

Application Process

Exam Pattern

Admit Card

National Institute of Open Schooling 10th examination

Admit Card Date:04 October,2024 - 29 November,2024

Application Process

Exam Pattern

Mock Test

Mizoram Board of School Education 12th Examination

Application Date:07 October,2024 - 22 November,2024

Exam Pattern

Result

Mock Test

Mizoram Board 10th Examination

Application Date:07 October,2024 - 22 November,2024

Exam Pattern

Admit Card

Result

Punjab Board of Secondary Education 10th Examination

Application Correction Date:08 October,2024 - 27 November,2024

Exam Pattern

Result

Admit Card

View All School Exams

Get answers from students and experts

Popular Questions

A block of mass 0.50 kg is moving with a speed of 2.00 ms^-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1) $0.34\; J$	Option 2) $0.16\; J$
Option 3) $1.00\; J$	Option 4) $0.67\; J$

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up ? Fat supplies 3.8×10⁷J of energy per kg which is converted to mechanical energy with a 20% efficiency rate. Take g = 9.8 ms⁻² :

Option 1)

2.45×10⁻³ kg

Option 2)

6.45×10⁻³ kg

Option 3)

9.89×10⁻³ kg

Option 4)

12.89×10⁻³ kg

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1) $2,000 \; J - 5,000\; J$	Option 2) $200 \, \, J - 500 \, \, J$
Option 3) $2\times 10^{5}J-3\times 10^{5}J$	Option 4) $20,000 \, \, J - 50,000 \, \, J$

A particle is projected at 60⁰ to the horizontal with a kinetic energy $K$ . The kinetic energy at the highest point

Option 1) $K/2\,$	Option 2) $\; K\;$
Option 3) $zero\;$	Option 4) $K/4$

In the reaction,

$2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}$

Option 1) $11.2\, L\, H_{2(g)}$ at STP is produced for every mole $HCL_{(aq)}$ consumed	Option 2) $6L\, HCl_{(aq)}$ is consumed for ever $3L\, H_{2(g)}$ produced
Option 3) $33.6 L\, H_{2(g)}$ is produced regardless of temperature and pressure for every mole Al that reacts	Option 4) $67.2\, L\, H_{2(g)}$ at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, $Mg_{3}(PO_{4})_{2}$ will contain 0.25 mole of oxygen atoms?

Option 1) 0.02	Option 2) 3.125 × 10^-2
Option 3) 1.25 × 10^-2	Option 4) 2.5 × 10^-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1) decrease twice	Option 2) increase two fold
Option 3) remain unchanged	Option 4) be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1) Molality	Option 2) Weight fraction of solute
Option 3) Fraction of solute present in water	Option 4) Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol^-1) is

Option 1) twice that in 60 g carbon	Option 2) 6.023 × 10²²
Option 3) half that in 8 g He	Option 4) 558.5 × 6.023 × 10²³

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t²) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m² , the number of rotations made by the pulley before its direction of motion if reversed, is