Table of Contents
✅ True or False (10 Questions)
(CBSE Class 8 Standard | Good Quality)
- A force is a push or pull acting on an object.
True hecu105
- Force can only change the speed of an object, not its direction.
False
(Force can change both speed and direction.) hecu105
- At least two objects are required for a force to come into play.
True hecu105
- The SI unit of force is newton (N).
True hecu105
- Muscular force is an example of a non-contact force.
False
(Muscular force is a contact force.) hecu105
- Friction always acts in the direction of motion of an object.
False
(Friction acts opposite to motion.) hecu105
- Magnetic force can act without physical contact between objects.
True hecu105
- Electrostatic force is produced due to charges built up by rubbing objects.
True hecu105
- Gravitational force is always attractive in nature.
True hecu105
- Mass of an object changes from place to place but weight remains constant.
False
(Mass remains constant, weight can change.)
✅ Fill in the Blanks (10 Questions)
(CBSE Class 8 Standard | Good Quality)
- A force is a push or a __________.
Answer: pull hecu105
- Force can change the speed, direction, or __________ of an object.
Answer: shape hecu105
- Force is always an interaction between at least __________ objects.
Answer: two hecu105
- The SI unit of force is __________.
Answer: newton hecu105
- Muscular force is an example of a __________ force.
Answer: contact hecu105
- Friction is a force that opposes the __________ of an object.
Answer: motion hecu105
- Magnetic force is a __________ force because it acts from a distance.
Answer: non-contact hecu105
- The force exerted by Earth on an object is called __________ force.
Answer: gravitational hecu105
- Weight of an object is measured using a __________ balance.
Answer: spring hecu105
- The upward force exerted by water on an object is called __________ force.
Answer: buoyant
✅ Multiple Choice Questions (15 MCQs)
(CBSE Class 8 Standard | Good Quality)
1. Force is defined as:
A. Only push
B. Only pull
C. Push or pull
D. Only motion
✅ Answer: C hecu105
2. The SI unit of force is:
A. Joule
B. Pascal
C. Newton
D. Watt
✅ Answer: C hecu105
3. Force can change the:
A. Shape of object
B. Speed of object
C. Direction of object
D. All of these
✅ Answer: D hecu105
4. A force always acts due to interaction between:
A. One object
B. Two objects
C. Three objects
D. No object
✅ Answer: B hecu105
5. Which of the following is a contact force?
A. Gravitational force
B. Magnetic force
C. Muscular force
D. Electrostatic force
✅ Answer: C hecu105
6. Friction acts in the direction:
A. Same as motion
B. Opposite to motion
C. Upward
D. Downward
✅ Answer: B hecu105
7. Which is a non-contact force?
A. Friction
B. Muscular force
C. Magnetic force
D. Push
✅ Answer: C hecu105
8. The force that pulls objects towards Earth is:
A. Magnetic force
B. Electrostatic force
C. Gravitational force
D. Muscular force
✅ Answer: C hecu105
9. Weight of an object depends on:
A. Mass only
B. Gravitational force
C. Shape
D. Colour
✅ Answer: B hecu105
10. Mass of an object is measured in:
A. Newton
B. Pascal
C. Kilogram
D. Metre
✅ Answer: C hecu105
11. Which instrument is used to measure weight?
A. Beam balance
B. Spring balance
C. Thermometer
D. Barometer
✅ Answer: B hecu105
12. Electrostatic force is produced due to:
A. Water
B. Charges on objects
C. Heat
D. Sound
✅ Answer: B hecu105
13. Buoyant force acts in the:
A. Downward direction
B. Upward direction
C. Horizontal direction
D. Circular direction
✅ Answer: B hecu105
14. An object floats in water if:
A. Its density is more than water
B. Its density is less than water
C. It has no mass
D. It has no weight
✅ Answer: B hecu105
15. Gravitational force is always:
A. Repulsive
B. Attractive
C. Neutral
D. Zero
✅ Answer: B
✅ Assertion–Reason Questions (10)
(CBSE Class 8 Standard | Good Quality)
Directions: Choose the correct option:
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
1.
Assertion (A): Force is a push or pull acting on an object.
Reason (R): Force can change the state of motion of an object.
✅ Answer: B hecu105
2.
Assertion (A): Force always arises due to interaction between two objects.
Reason (R): A single object cannot exert force on itself.
✅ Answer: A hecu105
3.
Assertion (A): Friction is a contact force.
Reason (R): Friction acts only when two surfaces are in contact.
✅ Answer: A hecu105
4.
Assertion (A): Magnetic force is a non-contact force.
Reason (R): A magnet can attract iron without touching it.
✅ Answer: A hecu105
5.
Assertion (A): Weight of an object changes from place to place.
Reason (R): Weight depends on gravitational force.
✅ Answer: A hecu105
6.
Assertion (A): Mass of an object remains constant everywhere.
Reason (R): Mass depends on the amount of matter in the object.
✅ Answer: A hecu105
7.
Assertion (A): Electrostatic force is produced due to electric charges.
Reason (R): Rubbing objects transfers charges between them.
✅ Answer: A hecu105
8.
Assertion (A): Buoyant force acts upward on an object in water.
Reason (R): Water exerts pressure on the object from below.
✅ Answer: A hecu105
9.
Assertion (A): An object floats if it is lighter than water.
Reason (R): Floating depends on the density of the object compared to water.
✅ Answer: B hecu105
10.
Assertion (A): Gravitational force is always attractive.
Reason (R): It pulls objects towards each other.
✅ Answer: A
✅ Very Short Answer Questions (10 Questions)
(2 Marks Each | CBSE Class 8 Standard | Good Quality)
1. What is force?
Answer:
Force is a push or pull acting on an object that can change its motion or shape. hecu105
2. What is the SI unit of force?
Answer:
The SI unit of force is newton (N). hecu105
3. Give one example of muscular force.
Answer:
Pushing a door or lifting a bag are examples of muscular force. hecu105
4. What is friction?
Answer:
Friction is the force that opposes the motion of an object when two surfaces are in contact. hecu105
5. Name one non-contact force.
Answer:
Magnetic force or gravitational force is a non-contact force. hecu105
6. What is gravitational force?
Answer:
Gravitational force is the force with which Earth attracts objects towards its centre. hecu105
7. How is weight measured?
Answer:
Weight is measured using a spring balance. hecu105
8. What is the difference between mass and weight?
Answer:
Mass is the amount of matter in an object and remains constant, while weight is the gravitational force on the object and changes with location. hecu105
9. What is buoyant force?
Answer:
Buoyant force is the upward force exerted by a liquid on an object immersed in it. hecu105
10. Why do objects float in water?
Answer:
Objects float if their density is less than that of water and buoyant force balances their weight.
✅ Short Answer Questions (10 Questions)
(3 Marks Each | CBSE Class 8 Standard | Good Quality)
1. What are the effects of force on an object?
Answer:
Force can produce several effects such as changing the speed of an object, changing its direction of motion, and changing its shape or size. Thus, force affects both motion and structure of objects. hecu105
2. Explain why force is called an interaction.
Answer:
Force is called an interaction because it always involves at least two objects. One object exerts force on another, and the other object experiences its effect. hecu105
3. Differentiate between contact and non-contact forces with examples.
Answer:
Contact forces act only when objects touch each other, like muscular force and friction. Non-contact forces act from a distance without contact, like gravitational, magnetic, and electrostatic forces. hecu105
4. What is friction? Mention one advantage and one disadvantage.
Answer:
Friction is a force that opposes motion between two surfaces in contact.
Advantage: Helps us walk without slipping.
Disadvantage: Causes wear and tear of machines. hecu105
5. Explain magnetic force with an example.
Answer:
Magnetic force is a non-contact force exerted by a magnet. Example: A magnet attracts iron nails even without touching them. hecu105
6. What is electrostatic force? How is it produced?
Answer:
Electrostatic force is the force exerted between charged objects. It is produced when objects are rubbed and electric charges build up on them. Example: A comb attracts paper pieces after rubbing. hecu105
7. Differentiate between mass and weight.
Answer:
Mass is the amount of matter in an object and remains constant everywhere. Weight is the gravitational force acting on the object and changes with location. Mass is measured in kilograms, weight in newtons. hecu105
8. What is buoyant force? Why does it act?
Answer:
Buoyant force is the upward force exerted by a liquid on an immersed object. It acts because liquid pressure is greater at the bottom of the object than at the top, producing an upward push. hecu105
9. Why do some objects float while others sink?
Answer:
An object floats if its density is less than water and buoyant force is greater than its weight. It sinks if its density is greater and weight exceeds buoyant force. hecu105
10. How is weight measured using a spring balance?
Answer:
A spring balance measures weight by the extension of a spring when an object is hung. Greater the weight, more the spring stretches, and the reading is shown in newtons.
✅ Case-Based Questions (4 Cases)
(4 Marks Each | Sub-questions: 1 + 1 + 2 Marks)
CBSE Competency-Based Standard
Case 1: Push and Pull in Daily Life
A student opens a door by pushing it. He also pulls a drawer to open it. Both actions involve force.
Questions:
Q1. (1 Mark) What is force?
Answer: Force is a push or pull acting on an object. hecu105
Q2. (1 Mark) Which type of force is used while opening a drawer?
Answer: Pull force hecu105
Q3. (2 Marks) Mention two effects of force.
Answer:
Force can change the speed of an object and can change its direction or shape. hecu105
Case 2: Friction in Walking
We are able to walk because friction acts between our feet and the ground. Without friction, we would slip.
Questions:
Q1. (1 Mark) What type of force is friction?
Answer: Contact force hecu105
Q2. (1 Mark) In which direction does friction act?
Answer: Opposite to motion hecu105
Q3. (2 Marks) Why is friction important for walking?
Answer:
Friction provides grip between our feet and the ground, preventing slipping and allowing us to walk. hecu105
Case 3: Magnetic Force
A magnet attracts iron nails without touching them. This shows that magnetic force can act from a distance.
Questions:
Q1. (1 Mark) Is magnetic force a contact or non-contact force?
Answer: Non-contact force hecu105
Q2. (1 Mark) Name one material attracted by magnets.
Answer: Iron hecu105
Q3. (2 Marks) Why is magnetic force called a non-contact force?
Answer:
Because a magnet can exert force on iron objects without physical contact. hecu105
Case 4: Floating and Buoyant Force
A piece of wood floats on water, while a stone sinks. This happens due to buoyant force and density differences.
Questions:
Q1. (1 Mark) What is buoyant force?
Answer: Upward force exerted by water on an immersed object. hecu105
Q2. (1 Mark) Which object has less density: wood or stone?
Answer: Wood hecu105
Q3. (2 Marks) Why does wood float but stone sinks?
Answer:
Wood floats because its density is less than water and buoyant force balances its weight. Stone sinks because its density is greater and weight exceeds buoyant force.
✅ Long Answer Questions (5 Questions)
(5 Marks Each | CBSE Class 8 Standard | High Quality Answers)
1. What is force? Explain the different effects of force with examples.
Answer:
Force is a push or pull acting on an object.
Effects of force:
- Change in speed: Force can start or stop motion.
Example: Kicking a football makes it move. - Change in direction: Force can change the direction of motion.
Example: A bat changes the direction of a moving ball. - Change in shape: Force can deform an object.
Example: Pressing a sponge changes its shape.
Thus, force affects motion and shape of objects. hecu105
2. Differentiate between contact and non-contact forces with examples.
Answer:
Forces are classified into two types:
Contact Forces
These forces act only when objects touch each other.
Examples:
- Muscular force
- Frictional force
Non-Contact Forces
These forces act from a distance without physical contact.
Examples:
- Gravitational force
- Magnetic force
- Electrostatic force
Thus, contact forces require touch while non-contact forces do not. hecu105
3. Explain friction and discuss its advantages and disadvantages.
Answer:
Friction is the force that opposes motion between two surfaces in contact.
Advantages:
- Helps us walk without slipping.
- Enables writing with pen or pencil.
- Helps vehicles move on roads.
Disadvantages:
- Causes wear and tear of machine parts.
- Produces heat and wastes energy.
- Slows down moving objects.
Thus, friction is useful but also creates problems. hecu105
4. Explain mass and weight. How are they different?
Answer:
Mass
- Amount of matter in an object.
- Remains constant everywhere.
- Measured in kilograms (kg).
Weight
- Force with which Earth attracts an object.
- Changes from place to place because gravity changes.
- Measured in newtons (N).
Thus, mass is constant while weight depends on gravity. hecu105
5. What is buoyant force? Explain why objects float or sink in water.
Answer:
Buoyant force is the upward force exerted by a liquid on an object immersed in it.
Floating and Sinking:
- If buoyant force is greater than the weight of the object, it floats.
Example: Wood floats. - If weight is greater than buoyant force, the object sinks.
Example: Stone sinks.
Density also plays a role: objects with density less than water float, while those with greater density sink.
Thus, buoyant force explains floating and sinking.