CBSE Class 8 Science Chapter 5: Exploring Forces — Assertion & Reason
CBSE Class 8 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions are based on Chapter 5: Exploring Forces from the NCERT Class 8 Science textbook Curiosity. Each question has four options — read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): At least two objects must interact for a force to come into play.
Reason (R): A force is defined as a push or pull on an object resulting from its interaction with another object.
Reason (R): A force is defined as a push or pull on an object resulting from its interaction with another object.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Forces cannot exist in isolation; they only result when two or more objects interact with each other in some way.
2
Assertion (A): Applying a force to an inflated balloon by pressing it between your hands changes its shape.
Reason (R): A force can only change the state of motion of an object, but not its shape.
Reason (R): A force can only change the state of motion of an object, but not its shape.
Answer: (c)
A is true, but R is false. A force can change the speed, direction of motion, and also bring about a change in the shape of an object (like stretching a rubber band or pressing a balloon).
3
Assertion (A): Muscular force is an example of a contact force.
Reason (R): Muscular force can only be applied when our body is in physical contact with the object, either directly or indirectly through a stick or rope.
Reason (R): Muscular force can only be applied when our body is in physical contact with the object, either directly or indirectly through a stick or rope.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because muscular force requires a physical connection to act upon an object, it is classified as a contact force.
4
Assertion (A): A ball rolling on a flat ground eventually stops on its own after travelling some distance.
Reason (R): The force of friction acts between the ball and the ground in a direction opposite to the ball's motion.
Reason (R): The force of friction acts between the ball and the ground in a direction opposite to the ball's motion.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Friction opposes the motion between two surfaces in contact, which gradually slows down the moving ball and brings it to a halt.
5
Assertion (A): The force of friction is exactly the same on all types of surfaces.
Reason (R): Friction arises due to the interlocking of minute irregularities between two surfaces in contact.
Reason (R): Friction arises due to the interlocking of minute irregularities between two surfaces in contact.
Answer: (d)
A is false, but R is true. Friction is not the same on all surfaces; it is greater on rough surfaces than on smooth ones because rougher surfaces have more irregularities that lock together.
6
Assertion (A): Magnetic force is considered a non-contact force.
Reason (R): A magnet can pull or push another magnet or a magnetic material from a distance without physically touching it.
Reason (R): A magnet can pull or push another magnet or a magnetic material from a distance without physically touching it.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Since magnetic force exerts its influence across an empty space without the need for physical contact, it is categorized as a non-contact force.
7
Assertion (A): Two inflated balloons rubbed with the same woollen cloth will attract each other when brought close.
Reason (R): Both balloons acquire similar static charges, and similar (like) charges repel each other.
Reason (R): Both balloons acquire similar static charges, and similar (like) charges repel each other.
Answer: (d)
A is false, but R is true. Because both balloons are rubbed with the same material, they acquire the same type of charge. Since like charges repel, the balloons will move away from each other, not attract.
8
Assertion (A): A plastic scale rubbed with polythene can attract small, uncharged pieces of paper.
Reason (R): The rubbed plastic scale acquires static charges and exerts an electrostatic force on the paper pieces.
Reason (R): The rubbed plastic scale acquires static charges and exerts an electrostatic force on the paper pieces.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The buildup of static electricity on the scale allows it to exert a non-contact electrostatic pull on the light, uncharged paper pieces.
9
Assertion (A): When a ball is thrown vertically upwards, its speed continuously decreases until it momentarily stops at the top.
Reason (R): The Earth exerts a downward gravitational pull that opposes the upward motion of the ball.
Reason (R): The Earth exerts a downward gravitational pull that opposes the upward motion of the ball.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The constant downward pull of the Earth's gravity decelerates the ball as it travels upward until its speed becomes zero.
10
Assertion (A): Gravitational force can sometimes act as a repulsive force that pushes objects away from the Earth.
Reason (R): The force with which the Earth attracts objects towards itself is called the gravitational force.
Reason (R): The force with which the Earth attracts objects towards itself is called the gravitational force.
Answer: (d)
A is false, but R is true. Unlike magnetic or electrostatic forces, gravitational force is exclusively an attractive force; it never repels objects.
11
Assertion (A): The mass of an object remains the same everywhere, but its weight can change from place to place.
Reason (R): Weight depends on the gravitational force pulling the object, which can vary slightly on Earth and is drastically different on other planets.
Reason (R): Weight depends on the gravitational force pulling the object, which can vary slightly on Earth and is drastically different on other planets.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Mass is the constant amount of matter in an object, while weight is a measure of local gravitational force, which fluctuates depending on location.
12
Assertion (A): A spring balance measures the weight of an object by determining how much the spring stretches.
Reason (R): The stretch caused in the spring of a balance is the same for all objects, regardless of their mass.
Reason (R): The stretch caused in the spring of a balance is the same for all objects, regardless of their mass.
Answer: (c)
A is true, but R is false. The amount a spring stretches is directly proportional to the downward force (weight) applied. Heavier objects will cause a greater stretch than lighter objects.
13
Assertion (A): In science, the correct SI unit of weight is the newton (N).
Reason (R): Weight is the gravitational force with which the Earth pulls an object towards itself.
Reason (R): Weight is the gravitational force with which the Earth pulls an object towards itself.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because weight is technically a measurement of force, it must be expressed in the SI unit of force, which is the newton.
14
Assertion (A): An empty, tightly closed plastic bottle pushed underwater will bounce back to the surface when released.
Reason (R): The water exerts an upward force called upthrust or buoyant force on the bottle.
Reason (R): The water exerts an upward force called upthrust or buoyant force on the bottle.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The liquid applies a strong upward buoyant force that exceeds the bottle's downward weight, causing it to shoot back up to the surface.
15
Assertion (A): Any object placed in a liquid will eventually sink to the bottom.
Reason (R): An object floats if the upward buoyant force applied by the liquid is equal to the downward gravitational force on the object.
Reason (R): An object floats if the upward buoyant force applied by the liquid is equal to the downward gravitational force on the object.
Answer: (d)
A is false, but R is true. Objects do not always sink. If the buoyant force (upthrust) balances or exceeds the downward force of gravity acting on the object, it will float.
❓ Frequently Asked Questions
What is covered in CBSE Class 8 Science Chapter 5 Exploring Forces?
This chapter covers all key topics from Exploring Forces as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 8 board exam preparation covering the complete syllabus.
Are these CBSE Class 8 Science Assertion & Reason updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 8 Science?
All chapters of CBSE Class 8 Science are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study Exploring Forces online for free?
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