NCERT Solutions For Class 8 Science Chapter 11 Force and Pressure

Force and pressure class 8 questions answers explain how pushes or pulls change an object's motion. This chapter explores how force acts on surfaces and defines pressure as force per unit area. By studying these solutions, you’ll master concepts like contact forces, atmospheric pressure, and liquid pressure, ensuring you can solve every textbook exercise with complete confidence and clarity.

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NCERT Solutions For Class 8 Science Chapter 11

Here we have provided NCERT Solutions for Class 8 Science Chapter 11 for the ease of students so that they can prepare better for their exams.

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

Solution:

Situations where you can push or pull objects to alter their motion include 1. Pull scenarios A drawer requires pulling to open. The drawer moves differently as a result of this movement. b) The rope is pulled to extract water from the well. The bucket's motion is altered by this movement. 2. Press circumstances a) A player's foot pushes the football. The ball's motion is altered by this move. b) We have to push the hefty box from one room to another to move it. The box's momentum is altered by this action.

Read More: NCERT Solutions for Class 8 Science Chapter 1

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

Solution:

The following are the forces that cause an item to alter shape: i) The clay deforms when pressed between the hands. ii) Squeezing the plastic container causes it to alter its shape.

3. 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.

Solution:

1. To draw water from a well, we have to pull at the rope.
2. A charged body attracts an uncharged body towards it.
3. To move a loaded trolley, we have to pull or push it.
4. The north pole of a magnet repels the north pole of another magnet.

4. An archer stretches her bow while aiming 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

Solution:

etch 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 friction of air.

Read More: NCERT Solutions for Class 8 Science Chapter 2

5. 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.

(b) Taking out paste from a toothpaste tube.

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

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

Solution:

a) We use our muscles to squeeze the lemon to get its juice. Consequently, the lemon's form is altered. b) We use our muscle power to extract the paste from the toothpaste tube. The toothpaste tube changes shape as a result of this muscle action. c) In this instance, the spring is forced downward by the hanging weight. The spring is subsequently stretched. Its form changes as a result. d) The athlete pushes the ground with his or her foot as they apply muscular force to it. They can now jump over the bar as a result. Their state of motion is subsequently altered.

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

Solution:

A blacksmith hammers a hot piece of iron using their muscular effort. The iron is shaped differently by the muscle power, allowing for the required shape to be applied to it.

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

Solution:

A piece of synthetic cloth rubbed across an inflated balloon causes it to become charged. An uncharged body is drawn to a charged one. This charged balloon adheres to the wall when it is shoved up against it. Therefore, between the charged balloon and the wall, there is an electrostatic force at work.

8. 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.

Solution:

We utilize our muscles to hold the pail of water above the ground. The force of gravity that draws the bucket towards the earth is opposed by this muscular force. While the two forces have the same magnitude, their directions are different. Consequently, there is no net force acting on the bucket. Thus, the motion's status remains unchanged.

Read More: NCERT Solutions for Class 8 Science Chapter 10

9. 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.

Solution:

The forces that draw the rocket towards the earth include gravity and friction caused by the earth's atmosphere, which prevents it from moving in the direction that it is intended to.

10. When we press the bulb of a dropper with its nozzle kept in water, the 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) pressure of water

(b) gravity of the earth

(c) the shape of a rubber bulb

(d) atmospheric pressure

Solution:

a) The air pressure is causing the water in the dropper to increase. The atmospheric pressure pressing on the water causes the water to fill the dropper's nozzle once all of the air has been forced out of it.

Master Force and Pressure Class 8 Questions Answers

Understanding physics starts with grasping how objects interact. In this section, we break down the core concepts found in your NCERT textbook. You’ll learn that force isn't just a simple push; it’s an interaction that can change speed, direction, or even the shape of an item.

Essential Concepts of Force

• Definition: A push or a pull on an object is called a force.

• Interaction: At least two objects must interact for a force to come into play.

• Magnitude: The strength of a force is usually expressed by its magnitude.

• State of Motion: Force can change the speed of an object or its direction of movement.

Key Types of Forces

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Explore Force and Pressure Class 8 Questions Answers PDF

Many students prefer a portable format for studying. Having a force and pressure class 8 questions answers pdf helps you revise while on the go. This document typically covers the exercise questions where you identify situations involving change in the state of motion or change in the shape of an object.

Examples of Force in Daily Life

1. Squeezing a Lemon: This is a clear example of force changing the shape of an object.

2. Taking an Injection: The doctor applies pressure to the plunger to push the liquid.

3. Moving a Magnet: A magnet can move iron without touching it, showing non-contact force.

4. Kicking a Ball: You apply muscular force to change the ball's speed and direction.

Identifying Force Actions

When you look at your textbook exercises, you'll see tasks asking you to classify actions as "push" or "pull." For instance, opening a drawer involves a pull, while hitting a cricket ball involves a push. Recognizing these small details makes the force and pressure class 8 questions answers much easier to remember during your exams.

Study Force and Pressure Class 8 Questions Answers Learn CBSE

To excel, you should follow the structure suggested by experts who focus on the learn CBSE pattern. This involves looking at how pressure works in fluids and gases. Pressure isn't just about solids; it’s a vital part of how our atmosphere and oceans behave every single day.

Understanding Pressure Fundamentals

• Formula: Pressure = Force / Area.

• Unit: The SI unit for pressure is the Pascal (Pa).

• Area Influence: If the area is smaller, the pressure for the same force is much higher.

• Tools: Porters place a round piece of cloth on their heads to increase surface area.

Pressure in Liquids and Gases

• Depth Matters: Pressure exerted by water at the bottom of a container is greater than at the top.

• Side Walls: Liquids exert pressure on the walls of the container they are kept in.

• Atmospheric Pressure: The air around us exerts a massive amount of pressure on our bodies.

• Balance: We don't feel atmospheric pressure because the pressure inside our bodies cancels it out.

Practice Force and Pressure Class 8 Questions Answers Extra

Regular textbook questions are great, but force and pressure class 8 questions answers extra help you think deeper. You might encounter questions about why tools used for cutting always have sharp edges. It's all about reducing the area to maximize the pressure applied by your hand.

Critical Thinking Scenarios

• Question: Why do school bags have wide straps?

• Answer: Wide straps increase the area of contact, which reduces the pressure on your shoulders.

• Question: Why does a sharp needle go into cloth easier than a blunt one?

• Answer: The tiny area of the sharp tip creates high pressure with very little force.

Non-Contact Forces Explained

Don't forget to study forces that act from a distance. Gravity is the most common one. It pulls everything toward the Earth. Without gravity, water wouldn't flow down a hill and we wouldn't stay grounded. Magnetic and electrostatic forces also fall into this category because they don't need physical contact to work.

Solve Force and Pressure Class 8 Questions Answers PDF MCQ

Multiple Choice Questions (MCQs) are a staple in modern exams. Using a force and pressure class 8 questions answers pdf mcq allows you to test your speed. These questions often focus on units, the difference between contact and non-contact forces, and the mathematical relationship between force, area, and pressure.

Quick Revision Checklist

• Units: Force is measured in Newtons (N).

• Net Force: If two forces act in opposite directions, the net force is their difference.

• Friction: This force always acts in the direction opposite to the motion.

• Atmosphere: The envelope of air surrounding the earth is called the atmosphere.

Practical Application Summary

When you're preparing for your finals, remember that physics is practical. If you push a wall, you're applying force, but there's no change in motion because the wall is sturdy. However, if you push a toy car, it zooms away. This distinction is what examiners love to test. Keep your answers short and use bullet points just like we've done here to score higher marks.

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Class 8 Science Chapter 11 Question Answer FAQs

1. What happens when two forces act in the same direction?

When two forces act in the same direction on an object, they add up. The total force is the sum of both individual forces, making the object move faster or with more strength.

2. Why do porters carry a cloth on their heads?

Porters use a round cloth to increase the surface area of contact with the load. This reduces the pressure on their heads, making it much easier to carry heavy suitcases.

3. Does pressure increase with depth in water?

Yes, pressure increases as you go deeper into a liquid. The weight of the water column above increases, which pushes down with more force on the objects below.

4. What is a non-contact force?

A non-contact force is a force that acts on an object without any physical touching. Examples include gravity pulling an apple down or a magnet attracting a small iron nail.