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All questions of Force Pairs for Grade 8 Exam
S.I. unit of pressure is- a)Celsius
- b)Newton
- c)Kelvin
- d)Pascal
Correct answer is option 'D'. Can you explain this answer?
S.I. unit of pressure is
a)
Celsius
b)
Newton
c)
Kelvin
d)
Pascal
|
Saranya Nair answered |
S.I. unit of pressure is Pascal. One Pascal is equal to one Newton per meter square.
A water tank has four taps fixed at points A, B, C, D as shown in Fig. 11.4. The water will flow out at the same pressure from taps at
- a)A and B
- b)C and D
- c)B and C
- d)A and C
Correct answer is option 'C'. Can you explain this answer?
A water tank has four taps fixed at points A, B, C, D as shown in Fig. 11.4. The water will flow out at the same pressure from taps at
a)
A and B
b)
C and D
c)
B and C
d)
A and C
|
Raghavi Iyer answered |
As we know liquids exert equal pressure at the same depth.
From the figure, B and C are at the same level, hence pressure will be the same at B and C.
From the figure, B and C are at the same level, hence pressure will be the same at B and C.
Which of the following is an example of contact force?- a)Muscular force
- b)Gravitational force
- c)Electrostatic force
- d)Magnetic force
Correct answer is option 'A'. Can you explain this answer?
Which of the following is an example of contact force?
a)
Muscular force
b)
Gravitational force
c)
Electrostatic force
d)
Magnetic force
|
Kavya Chopra answered |
The forces in which to bodies acting on each other are in contact are called contact force. Muscular force is an example of contact force.
Gravitational force is acting on- a)Only on moon
- b)Only on other planets
- c)Only on earth
- d)All bodies
Correct answer is option 'D'. Can you explain this answer?
Gravitational force is acting on
a)
Only on moon
b)
Only on other planets
c)
Only on earth
d)
All bodies
|
|
Amit Kumar answered |
Gravitational force is acting on earth, moon and on all other planet. This force is acting on all the body having some mass.
When pressing the bulb of a dropper with its nozzle in water, what causes water to rise in the dropper when pressure is released?- a)Pressure of water
- b)Gravity of the earth
- c)Shape of the rubber bulb
- d)Atmospheric pressure
Correct answer is option 'D'. Can you explain this answer?
When pressing the bulb of a dropper with its nozzle in water, what causes water to rise in the dropper when pressure is released?
a)
Pressure of water
b)
Gravity of the earth
c)
Shape of the rubber bulb
d)
Atmospheric pressure
|
Prepworks Coaching answered |
Releasing the bulb creates a lower pressure inside, causing water to rise due to atmospheric pressure, demonstrating fluid dynamics.
The strength of a force is usually expressed by its- a)Altitude
- b)Duration
- c)Direction
- d)Magnitude
Correct answer is 'D'. Can you explain this answer?
The strength of a force is usually expressed by its
a)
Altitude
b)
Duration
c)
Direction
d)
Magnitude
|
Dipika Mukherjee answered |
Force is a vector quantity as it contains both direction and magnitude but strength of a force is usually expressed by its magnitude.
Perpendicular force acting per unit area is called is called- a)Power
- b)Work
- c)Pressure
- d)Energy
Correct answer is option 'C'. Can you explain this answer?
Perpendicular force acting per unit area is called is called
a)
Power
b)
Work
c)
Pressure
d)
Energy
|
|
Amit Sharma answered |
The total force acting perpendicular on a given surface is called thrust. Thrust acting upon a unit area is called pressure.
A force has- a)Only direction
- b)Both magnitude and direction absent
- c)Both magnitude and direction
- d)Only magnitude
Correct answer is option 'C'. Can you explain this answer?
A force has
a)
Only direction
b)
Both magnitude and direction absent
c)
Both magnitude and direction
d)
Only magnitude
|
Sanjana Bose answered |
A force can cause an object with mass to change its velocity(which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a pushor a pull. A force has both magnitude and direction, making it a vector quantity.
The force exerted by a charged body on another charged or uncharged body is known as- a)Magnetic force
- b)Gravitational force
- c)Electrostatic force
- d)Muscular force
Correct answer is option 'C'. Can you explain this answer?
The force exerted by a charged body on another charged or uncharged body is known as
a)
Magnetic force
b)
Gravitational force
c)
Electrostatic force
d)
Muscular force
|
Pranab Chawla answered |
The force exerted by a charged body on another charged or uncharged body is known as electrostatic force. Electrostatic force is non-contact force.
Friction arises due to- a)Contact between surfaces
- b)Repulsion between surfaces
- c)Attraction between surfaces
- d)All of the above
Correct answer is option 'A'. Can you explain this answer?
Friction arises due to
a)
Contact between surfaces
b)
Repulsion between surfaces
c)
Attraction between surfaces
d)
All of the above
|
Pritam Sen answered |
Friction arises due to contact between two surfaces. Friction force is more in case of solid body and less in case of gases.
The tendency of a body to maintain its state of rest or uniform motion is called- a)Gravity
- b)Inertia
- c)Weight
- d)Acceleration
Correct answer is option 'B'. Can you explain this answer?
The tendency of a body to maintain its state of rest or uniform motion is called
a)
Gravity
b)
Inertia
c)
Weight
d)
Acceleration
|
|
Sanjana Bose answered |
The tendency of an object to maintain its state of motion, to remain at rest or to keep moving at a constant velocity, is known as inertia.
What is the cause of change in motion or change in the state of motion?- a)Pressure
- b)Atmospheric Pressure
- c)Force
- d)Friction
Correct answer is option 'C'. Can you explain this answer?
What is the cause of change in motion or change in the state of motion?
a)
Pressure
b)
Atmospheric Pressure
c)
Force
d)
Friction
|
Sara Nair answered |
When force is applied to any object it may change its direction eg.foot ball it may change its shape eg dough it may change its state it may change its motion.
Which force enables us to perform all activities involving movement or bending of our body?- a)Frictional force
- b)Magnetic force
- c)Electrostatic force
- d)Muscular force
Correct answer is option 'D'. Can you explain this answer?
Which force enables us to perform all activities involving movement or bending of our body?
a)
Frictional force
b)
Magnetic force
c)
Electrostatic force
d)
Muscular force
|
Geetika Shah answered |
Muscular force enables us to perform all activities involving movement or bending of our body. Muscular force is developed inside muscle due to presence of contractile protein.
When a rocket is fired upwards, what forces act on it immediately after leaving the launch pad?
- a)Gravity and magnetic force
- b)gravitational force and frictional force
- c)Friction and Magnetic Force
- d)Electrostatic force and thrust
Correct answer is option 'B'. Can you explain this answer?
When a rocket is fired upwards, what forces act on it immediately after leaving the launch pad?
a)
Gravity and magnetic force
b)
gravitational force and frictional force
c)
Friction and Magnetic Force
d)
Electrostatic force and thrust
|
Flembe Academy answered |
The thrust from the rocket engines and gravity act on the rocket, illustrating the forces involved in launching a rocket.
Why does an inflated balloon stick to a wall after being rubbed with a synthetic cloth?- a)Gravitational force
- b)Magnetic force
- c)Electrostatic force
- d)Contact force
Correct answer is option 'C'. Can you explain this answer?
Why does an inflated balloon stick to a wall after being rubbed with a synthetic cloth?
a)
Gravitational force
b)
Magnetic force
c)
Electrostatic force
d)
Contact force
|
Future Foundation Institute answered |
Rubbing creates an electrostatic charge, causing the balloon to stick, demonstrating electrostatic forces.
Why do the forces acting on a held plastic bucket not change its state of motion?- a)The forces are balanced
- b)The forces are unbalanced
- c)Only gravity acts
- d)Only muscular force acts
Correct answer is option 'A'. Can you explain this answer?
Why do the forces acting on a held plastic bucket not change its state of motion?
a)
The forces are balanced
b)
The forces are unbalanced
c)
Only gravity acts
d)
Only muscular force acts
|
S.S Career Academy answered |
The muscular force balances the gravitational force, keeping the bucket stationary, illustrating balanced forces.
When a load is suspended from a spring, what happens to the spring?- a) The spring pulls the load, creating a gravitational pull
- b) The load pulls the spring, causing it to stretch
- c) The hook compresses the spring, changing its shape
- d) The wall moves the hook, changing its motion
Correct answer is option 'B'. Can you explain this answer?
When a load is suspended from a spring, what happens to the spring?
a)
The spring pulls the load, creating a gravitational pull
b)
The load pulls the spring, causing it to stretch
c)
The hook compresses the spring, changing its shape
d)
The wall moves the hook, changing its motion
|
BT Educators answered |
When a load is suspended from a spring, the load pulls the spring, causing it to stretch. This phenomenon can be explained by Hooke's law, which describes the relationship between the force applied to the spring and the resulting extension or compression of the spring. This demonstrates the concept of elastic deformation in materials subjected to external forces.
Electrostatic force is exerted by charged body on- a)Another charged body or uncharged body
- b)Metallic body only
- c)Another uncharged body only
- d)Another charged body only
Correct answer is option 'A'. Can you explain this answer?
Electrostatic force is exerted by charged body on
a)
Another charged body or uncharged body
b)
Metallic body only
c)
Another uncharged body only
d)
Another charged body only
|
Harsh Datta answered |
Electrostatic force is exerted by charged body on another charged body or uncharged body. Two charged body having same kind of charge repels each other.
When a force is applied to a body and it moves in the direction of the applied force, which of the following is true?- a)The body does not change its shape.
- b)The force does not change the state of motion.
- c)The force causes the body to accelerate.
- d)The force decreases the speed of the body.
Correct answer is option 'C'. Can you explain this answer?
When a force is applied to a body and it moves in the direction of the applied force, which of the following is true?
a)
The body does not change its shape.
b)
The force does not change the state of motion.
c)
The force causes the body to accelerate.
d)
The force decreases the speed of the body.
|
Bespoke Classes answered |
When a force is applied to a body, it can change the body's state of motion. If the force is applied in the direction of the body's motion, it causes the body to accelerate, meaning the speed of the body increases. This is in accordance with Newton's second law of motion, which states that force equals mass times acceleration (F=maF = maF=ma). Thus, the application of force in the direction of motion leads to acceleration.
State whether the following statement is True or False:A magnet can exert a force on another magnet without being in contact with it.- a) True
- b) False
Correct answer is option 'A'. Can you explain this answer?
State whether the following statement is True or False:
A magnet can exert a force on another magnet without being in contact with it.
a)
True
b)
False
|
|
Flembe Academy answered |
- Yes, it's true! Imagine magnets as magic friends.
- They can push or pull each other from a distance without even touching.
- Just like how you can make a toy car move without touching it, magnets can do the same thing.
- It's like they have invisible hands that can reach out and interact with each other!
The force resulting due to the action of muscles is known as the- a)Frictional force
- b)Gravitational force
- c)Muscular force
- d)Magnetic force
Correct answer is option 'C'. Can you explain this answer?
The force resulting due to the action of muscles is known as the
a)
Frictional force
b)
Gravitational force
c)
Muscular force
d)
Magnetic force
|
Mihir Shah answered |
The force resulting due to the action of muscles is known as the muscular force. Muscular force is present in all animals including human beings.
Force of gravity is a- a)Repulsive force
- b)Attractive force
- c)Contact force
- d)Neither attractive nor repulsive force
Correct answer is option 'B'. Can you explain this answer?
Force of gravity is a
a)
Repulsive force
b)
Attractive force
c)
Contact force
d)
Neither attractive nor repulsive force
|
Anu Choudhury answered |
The force of gravity is a attractive force. Every object in universe attracts every other object. This attractive force is called gravity.
What force does an athlete exert when making a high jump?- a)Athlete pushes the ground, moving upwards
- b)Bar pulls the athlete, lifting them higher
- c)Air pushes the athlete, causing resistance
- d)Ground pulls the athlete, keeping them stable
Correct answer is option 'A'. Can you explain this answer?
What force does an athlete exert when making a high jump?
a)
Athlete pushes the ground, moving upwards
b)
Bar pulls the athlete, lifting them higher
c)
Air pushes the athlete, causing resistance
d)
Ground pulls the athlete, keeping them stable
|
Lakshya Ias answered |
The athlete pushes against the ground to jump, showing how force can change motion.
Like poles of magnet- a)Repels each other
- b)Attach with each other
- c)Either attract or repels
- d)Attract each other
Correct answer is option 'A'. Can you explain this answer?
Like poles of magnet
a)
Repels each other
b)
Attach with each other
c)
Either attract or repels
d)
Attract each other
|
|
Shivani Kaur answered |
Like poles of magnet repels each other while unlike poles of two magnet attract each other.
Which of the following is responsible for changing the state of motion of an object?- a)Temperature
- b)Force
- c)Friction
- d)Heat
Correct answer is option 'B'. Can you explain this answer?
Which of the following is responsible for changing the state of motion of an object?
a)
Temperature
b)
Force
c)
Friction
d)
Heat
|
Deepak Pillai answered |
Understanding Forces
Force is a fundamental concept in physics that describes an interaction that causes an object to change its state of motion.
What is Force?
- A force is a vector quantity, which means it has both magnitude and direction.
- It can cause an object to start moving, stop moving, speed up, slow down, or change direction.
How Force Changes Motion
- According to Newton's First Law of Motion, an object at rest will remain at rest, and an object in motion will continue in motion at a constant velocity unless acted upon by a net external force.
- When a force is applied to an object, it can overcome inertia (the tendency of an object to resist changes in its state of motion) and initiate movement or alter its trajectory.
Examples of Force in Action
- Pushing a Door: When you push a door, the force you apply changes its state from closed to open.
- Throwing a Ball: The force exerted by your hand changes the ball's state from resting to moving.
Other Options Explained
- Temperature: Refers to the measure of heat and does not directly change motion.
- Friction: While it opposes motion, it does not initiate motion or change the state; it can slow down or stop an object.
- Heat: A form of energy transfer but does not directly change the state of motion.
Conclusion
In conclusion, the correct answer is option 'B', Force, as it is the key factor responsible for changing the state of motion of an object. Understanding forces is crucial for grasping the principles of physics and how objects interact in the physical world.
Force is a fundamental concept in physics that describes an interaction that causes an object to change its state of motion.
What is Force?
- A force is a vector quantity, which means it has both magnitude and direction.
- It can cause an object to start moving, stop moving, speed up, slow down, or change direction.
How Force Changes Motion
- According to Newton's First Law of Motion, an object at rest will remain at rest, and an object in motion will continue in motion at a constant velocity unless acted upon by a net external force.
- When a force is applied to an object, it can overcome inertia (the tendency of an object to resist changes in its state of motion) and initiate movement or alter its trajectory.
Examples of Force in Action
- Pushing a Door: When you push a door, the force you apply changes its state from closed to open.
- Throwing a Ball: The force exerted by your hand changes the ball's state from resting to moving.
Other Options Explained
- Temperature: Refers to the measure of heat and does not directly change motion.
- Friction: While it opposes motion, it does not initiate motion or change the state; it can slow down or stop an object.
- Heat: A form of energy transfer but does not directly change the state of motion.
Conclusion
In conclusion, the correct answer is option 'B', Force, as it is the key factor responsible for changing the state of motion of an object. Understanding forces is crucial for grasping the principles of physics and how objects interact in the physical world.
Leaves or fruits fall on the ground due to - a)magnetic force
- b)gravitational force
- c)electrostatic force
- d)muscular force
Correct answer is option 'B'. Can you explain this answer?
Leaves or fruits fall on the ground due to
a)
magnetic force
b)
gravitational force
c)
electrostatic force
d)
muscular force
|
|
Aruna Singh answered |
Leaves or fruits fall on the ground due to gravitational force. Gravitational force is the force of attraction between two objects with mass. It is what keeps all of the planets in orbit around the sun and what causes objects to fall towards the ground when dropped. The other forces listed, such as magnetic force, electrostatic force, and muscular force, are not responsible for causing leaves or fruits to fall on the ground.
State whether the following statement is True or False:
When you push a ball gently along a level surface, it does not move.
- a)True
- b)False
Correct answer is option 'B'. Can you explain this answer?
State whether the following statement is True or False:
When you push a ball gently along a level surface, it does not move.
a)
True
b)
False
|
|
Flembe Academy answered |
- When you push a ball gently along a level surface, it usually starts to move.
- Imagine you have a ball on a table. If you give it a little push, it will likely start rolling. This happens because the force you apply makes the ball move. So, the correct answer is False. When you push a ball gently on a level surface, it tends to move.
Which one is an example that shows that force can change shape and size of object?- a)Force applied to increase the speed
- b)Force applied on cricket ball
- c)Force applied on large stone
- d)Force applied on inflated balloon
Correct answer is option 'D'. Can you explain this answer?
Which one is an example that shows that force can change shape and size of object?
a)
Force applied to increase the speed
b)
Force applied on cricket ball
c)
Force applied on large stone
d)
Force applied on inflated balloon
|
Anirudh Pillai answered |
Force applied on inflated balloon
When a force is applied on an inflated balloon, it can change the shape and size of the balloon. This is because the force exerts pressure on the air molecules inside the balloon, causing them to spread out and expand.
The force applied on the inflated balloon can be explained using the concept of air pressure. Air molecules inside the balloon exert a certain amount of pressure in all directions. This pressure is evenly distributed throughout the balloon, keeping it in a round shape.
However, when an external force is applied to the balloon, such as squeezing or pressing it, the force compresses the air molecules inside. This compression increases the pressure exerted by the air molecules, causing them to push against the walls of the balloon.
As a result, the balloon changes its shape and size. If the force applied is strong enough, the balloon may even burst. The force applied can stretch the balloon in different directions, making it elongated or distorted.
The change in shape and size of the balloon is temporary and depends on the force applied. Once the force is removed, the balloon will return to its original shape and size, as the air molecules inside regain their equilibrium.
This example demonstrates the effect of force on an object's shape and size. It shows that force can cause deformation or distortion in an object, depending on the strength and direction of the force applied.
When a force is applied on an inflated balloon, it can change the shape and size of the balloon. This is because the force exerts pressure on the air molecules inside the balloon, causing them to spread out and expand.
The force applied on the inflated balloon can be explained using the concept of air pressure. Air molecules inside the balloon exert a certain amount of pressure in all directions. This pressure is evenly distributed throughout the balloon, keeping it in a round shape.
However, when an external force is applied to the balloon, such as squeezing or pressing it, the force compresses the air molecules inside. This compression increases the pressure exerted by the air molecules, causing them to push against the walls of the balloon.
As a result, the balloon changes its shape and size. If the force applied is strong enough, the balloon may even burst. The force applied can stretch the balloon in different directions, making it elongated or distorted.
The change in shape and size of the balloon is temporary and depends on the force applied. Once the force is removed, the balloon will return to its original shape and size, as the air molecules inside regain their equilibrium.
This example demonstrates the effect of force on an object's shape and size. It shows that force can cause deformation or distortion in an object, depending on the strength and direction of the force applied.
The speed of moving ball increase further if force is applied in- a)Opposite to direction of motion
- b)Parallel to direction of motion
- c)Direction of motion
- d)Perpendicular to direction of motion
Correct answer is option 'C'. Can you explain this answer?
The speed of moving ball increase further if force is applied in
a)
Opposite to direction of motion
b)
Parallel to direction of motion
c)
Direction of motion
d)
Perpendicular to direction of motion
|
Raghavendra Jain answered |
The speed of moving ball increase further if force is applied in direction of motion and decrease if force is applied in opposite direction.
Force applied on an object in same direction- a)Divide on another
- b)Add to one another
- c)Multiply on another
- d)Subtract to one another
Correct answer is option 'B'. Can you explain this answer?
Force applied on an object in same direction
a)
Divide on another
b)
Add to one another
c)
Multiply on another
d)
Subtract to one another
|
Trisha Vashisht answered |
When a force is applied on an object in the same direction as its motion, it results in an increase in speed.
Conversely, if a force is applied in the opposite direction, it causes a decrease in speed.
- Forces acting in the same direction add together.
- Forces acting in opposite directions subtract from one another.
- The net force determines the overall effect on the object's motion.
When two forces act in opposite directions, what is the net force acting on the object?- a) Sum of the two forces
- b) Difference between the two forces
- c) Both of these
- d) None of these
Correct answer is option 'B'. Can you explain this answer?
When two forces act in opposite directions, what is the net force acting on the object?
a)
Sum of the two forces
b)
Difference between the two forces
c)
Both of these
d)
None of these
|
EduRev Class 8 answered |
When two forces act in opposite directions, the net force is found by subtracting the smaller force from the larger one. The direction of the net force will be in the direction of the larger force. If both forces were acting in the same direction, you would add them. Therefore, the net force is the difference between the two forces when they act in opposite directions.
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