All questions of Forces in Two Dimensions for Grade 9 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.
Magnetic force is- a)Contact force
- b)Non-contact force
- c)both (a) and (b)
- d)None.
Correct answer is option 'B'. Can you explain this answer?
Magnetic force is
a)
Contact force
b)
Non-contact force
c)
both (a) and (b)
d)
None.
|
|
Amit Sharma answered |
Magnetic forces are non - contact forces; they pull or push on objects without touching them. Magnets are only attracted to a few 'magnetic' metals and not all matter.
Force is a- a)Pull
- b)Push
- c)Pull and push both
- d)None of these.
Correct answer is option 'C'. Can you explain this answer?
Force is a
a)
Pull
b)
Push
c)
Pull and push both
d)
None of these.
|
Khushi Singh answered |
If we push or pull any object we use force to push or pull it. So... Force is both push and pull.
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.
The force exerted per unit area is called magnitude.- a)True
- b)False
Correct answer is option 'B'. Can you explain this answer?
The force exerted per unit area is called magnitude.
a)
True
b)
False
|
|
Amit Sharma answered |
The correct answer is B as force exerted per unit area is called pressure.
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.
The strength of force is expressed by
- a)Weight
- b)Mass
- c)(Magnitude) Newton
- d)Longitudinal force.
Correct answer is option 'C'. Can you explain this answer?
The strength of force is expressed by
a)
Weight
b)
Mass
c)
(Magnitude) Newton
d)
Longitudinal force.
|
Niti Banerjee answered |
The correct answer is option 'C' - Magnitude.
Force is a physical quantity that is used to describe the interaction between objects. It can cause objects to accelerate, decelerate, or change direction. The strength of force is expressed by its magnitude, which refers to the size or quantity of the force.
Here's a detailed explanation of the other options and why they are not the correct answers:
a) Weight:
Weight is the force experienced by an object due to gravity. It is the measure of the gravitational force acting on an object's mass. While weight is a measure of force, it is not the same as the strength of force. Weight depends on the mass and the acceleration due to gravity, but the strength of force is a more general term that can encompass other types of forces beyond gravity.
b) Mass:
Mass is a measure of the amount of matter in an object. It is a scalar quantity and is not directly related to the strength of force. However, the mass of an object does affect the force required to accelerate it. According to Newton's second law of motion, the force acting on an object is equal to the mass of the object multiplied by its acceleration. So while mass is not the strength of force, it is related to the force required to produce a certain acceleration.
d) Longitudinal force:
Longitudinal force refers to a force that acts in the same direction as an object's motion. It is a type of force that can cause objects to accelerate or decelerate. However, it is not a measure of the strength of force in general. The magnitude of a longitudinal force would be a measure of its strength, but the term "longitudinal force" itself does not inherently imply the strength of force.
In conclusion, the strength of force is expressed by its magnitude, which refers to the size or quantity of the force. Other factors such as weight, mass, and the direction of force are related to force but do not directly measure its strength.
Force is a physical quantity that is used to describe the interaction between objects. It can cause objects to accelerate, decelerate, or change direction. The strength of force is expressed by its magnitude, which refers to the size or quantity of the force.
Here's a detailed explanation of the other options and why they are not the correct answers:
a) Weight:
Weight is the force experienced by an object due to gravity. It is the measure of the gravitational force acting on an object's mass. While weight is a measure of force, it is not the same as the strength of force. Weight depends on the mass and the acceleration due to gravity, but the strength of force is a more general term that can encompass other types of forces beyond gravity.
b) Mass:
Mass is a measure of the amount of matter in an object. It is a scalar quantity and is not directly related to the strength of force. However, the mass of an object does affect the force required to accelerate it. According to Newton's second law of motion, the force acting on an object is equal to the mass of the object multiplied by its acceleration. So while mass is not the strength of force, it is related to the force required to produce a certain acceleration.
d) Longitudinal force:
Longitudinal force refers to a force that acts in the same direction as an object's motion. It is a type of force that can cause objects to accelerate or decelerate. However, it is not a measure of the strength of force in general. The magnitude of a longitudinal force would be a measure of its strength, but the term "longitudinal force" itself does not inherently imply the strength of force.
In conclusion, the strength of force is expressed by its magnitude, which refers to the size or quantity of the force. Other factors such as weight, mass, and the direction of force are related to force but do not directly measure its strength.
State of motion is described by
- a)Object's speed
- b)Object's size
- c)A reference point
- d)Object's mass
Correct answer is option 'C'. Can you explain this answer?
State of motion is described by
a)
Object's speed
b)
Object's size
c)
A reference point
d)
Object's mass
|
Sanjana Bose answered |
The state of rest or motion of an object is defined using a reference point. The reference point is a point used to describe the location of something. An object is said to be in motion, if it changes its position relative to the reference point. The mass, volume and size of the object are not necessary to describe whether the object is at rest or in motion.
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.
The force between two charged bodies is called
- a)Muscular force
- b)Gravitational force
- c)Magnetic force
- d)Electrostatic force.
Correct answer is option 'D'. Can you explain this answer?
The force between two charged bodies is called
a)
Muscular force
b)
Gravitational force
c)
Magnetic force
d)
Electrostatic force.
|
Shubham Sharma answered |
The force between two charged bodies is called:
- Electrostatic force.
Solution:
- The electric force between two charged bodies at rest is known as electrostatic force or Coulomb force.
- This force is described by Coulomb's law, which states that the magnitude of the electrostatic force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
- Electrostatic forces can be either attractive or repulsive depending on the nature of the charges involved.The electric force between two charged bodies at rest is conventionally called electrostatic force or Coulomb force.
- Electrostatic force.
Solution:
- The electric force between two charged bodies at rest is known as electrostatic force or Coulomb force.
- This force is described by Coulomb's law, which states that the magnitude of the electrostatic force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
- Electrostatic forces can be either attractive or repulsive depending on the nature of the charges involved.The electric force between two charged bodies at rest is conventionally called electrostatic force or Coulomb force.
To move at the same speed, a car with a flat face and another with a streamlined body will require a different amount of force from the engine. The engine of the streamline bodied car will:- a) Exert more force
- b)Exert less force
- c)Exert zero force
- d)Exert no force
Correct answer is option 'B'. Can you explain this answer?
To move at the same speed, a car with a flat face and another with a streamlined body will require a different amount of force from the engine. The engine of the streamline bodied car will:
a)
Exert more force
b)
Exert less force
c)
Exert zero force
d)
Exert no force
|
EduRev Class 8 answered |
Friction opposes the relative motion between two surfaces in contact. Fluid friction can be minimized by giving suitable shapes to bodies moving in fluids. A car with a streamlined body suffers less air friction while moving and a car with a flat face will suffer higher air friction. As a result car with a streamlined body will require less force from the engine to maintain the same speed.
Force of friction is an example of non-contact force.- a)True
- b)False
Correct answer is option 'B'. Can you explain this answer?
Force of friction is an example of non-contact force.
a)
True
b)
False
|
|
Bhavana Patel answered |
**False**
Friction is a type of force that opposes the relative motion between two surfaces in contact. It acts parallel to the surface and opposes the motion or tendency of motion between the surfaces. Therefore, friction is an example of a contact force, not a non-contact force.
Friction can occur between solid surfaces, such as when you try to slide a heavy box across the floor. It can also occur between a solid and a fluid, such as air resistance when an object moves through the air. In both cases, the surfaces must be in contact for friction to occur.
**Contact Forces vs Non-Contact Forces:**
Contact forces are those forces that require direct contact between two objects or substances for them to occur. Examples of contact forces include friction, normal force, tension force, and applied force. These forces are exerted through physical contact between the objects involved.
On the other hand, non-contact forces are forces that act on an object without any direct physical contact. These forces can act over a distance and do not require any physical contact between the objects involved. Examples of non-contact forces include gravitational force, magnetic force, and electrostatic force.
**Explanation:**
Friction is a contact force because it requires the surfaces of two objects to be in contact in order to occur. When two surfaces are in contact, the microscopic irregularities on the surfaces interact with each other, causing resistance to motion. This resistance is what we experience as friction.
For example, if you try to slide a heavy box across the floor, the roughness of the floor and the box's surface interact, creating friction that opposes the motion. If there was no contact between the box and the floor, there would be no friction and the box would easily slide without any resistance.
Therefore, since friction requires contact between surfaces to occur, it is not an example of a non-contact force but rather a contact force.
Friction is a type of force that opposes the relative motion between two surfaces in contact. It acts parallel to the surface and opposes the motion or tendency of motion between the surfaces. Therefore, friction is an example of a contact force, not a non-contact force.
Friction can occur between solid surfaces, such as when you try to slide a heavy box across the floor. It can also occur between a solid and a fluid, such as air resistance when an object moves through the air. In both cases, the surfaces must be in contact for friction to occur.
**Contact Forces vs Non-Contact Forces:**
Contact forces are those forces that require direct contact between two objects or substances for them to occur. Examples of contact forces include friction, normal force, tension force, and applied force. These forces are exerted through physical contact between the objects involved.
On the other hand, non-contact forces are forces that act on an object without any direct physical contact. These forces can act over a distance and do not require any physical contact between the objects involved. Examples of non-contact forces include gravitational force, magnetic force, and electrostatic force.
**Explanation:**
Friction is a contact force because it requires the surfaces of two objects to be in contact in order to occur. When two surfaces are in contact, the microscopic irregularities on the surfaces interact with each other, causing resistance to motion. This resistance is what we experience as friction.
For example, if you try to slide a heavy box across the floor, the roughness of the floor and the box's surface interact, creating friction that opposes the motion. If there was no contact between the box and the floor, there would be no friction and the box would easily slide without any resistance.
Therefore, since friction requires contact between surfaces to occur, it is not an example of a non-contact force but rather a contact force.
When two forces act in opposite directions, then net force acting is the- a)Sum of two forces
- b)Difference between 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, then net force acting is the
a)
Sum of two forces
b)
Difference between two forces
c)
Both of these
d)
None of these.
|
Ritu Joshi answered |
When forces are applied on an object in same direction the net force increases .When force are applied on an object on an object in opp directions the net force on the object is difference between 2 forces.
A wooden piece 5N in weight and 5cm x 3cm x 2cm in size lies on 5cm x 2cm face. The pressure exerted by it in N per cm2 is:- a)150
- b)50
- c)0.5
- d)15
Correct answer is option 'C'. Can you explain this answer?
A wooden piece 5N in weight and 5cm x 3cm x 2cm in size lies on 5cm x 2cm face. The pressure exerted by it in N per cm2 is:
a)
150
b)
50
c)
0.5
d)
15
|
C K Academy answered |
The correct calculation for the pressure exerted by the wooden piece should be considered.
Pressure is defined as force per unit area.
The wooden piece has a weight (force) of 5 N and lies on a face with dimensions 5 cm x 2 cm, giving an area of 5 × 2 = 10 cm². Therefore, the pressure exerted by the wooden piece is calculated as 5 N / 10 cm² = 0.5 N/cm². The correct answer is option 3, which is 0.5.
Pressure is defined as force per unit area.
The wooden piece has a weight (force) of 5 N and lies on a face with dimensions 5 cm x 2 cm, giving an area of 5 × 2 = 10 cm². Therefore, the pressure exerted by the wooden piece is calculated as 5 N / 10 cm² = 0.5 N/cm². The correct answer is option 3, which is 0.5.
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.
Force acts on an object may change- a)Direction
- b)Shape
- c)Speed
- d)All of above.
Correct answer is option 'D'. Can you explain this answer?
Force acts on an object may change
a)
Direction
b)
Shape
c)
Speed
d)
All of above.
|
Pavithra Pravin answered |
Force is the push or pull activity on an object. It has the following properties : 1) Force can change the direction of a moving object. For example, we can change the direction of a moving ball by kicking it in another direction. 2) Force can change the shape of an object. For example, we can change the shape of a paper by crumbling it. 3) Force can change the speed by making a moving object move faster. For example, we can change the speed of a ball by kicking it. 4) Force can stop or slow down a moving object. For example, we can catch a falling ball and can thus stop it from falling. 5) Force can move an object in rest. For example, we can move a chair by pulling it.
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.
If two forces act in opposite directions on an object, the net force is the difference between the two forces.
- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
If two forces act in opposite directions on an object, the net force is the difference between the two forces.
a)
True
b)
False
|
Indu Gupta answered |
Explanation:
The statement is False.
When two forces act in opposite directions on an object, the net force is determined by the sum of the magnitudes of the two forces. The net force is not the difference between the two forces.
Here's a detailed explanation:
1. Definition of net force: Net force is the vector sum of all the individual forces acting on an object. It describes the overall effect of all the forces combined.
2. Opposite forces: When two forces act in opposite directions, they cancel each other out to some extent.
3. Equal magnitude opposite forces: If the two forces have equal magnitudes, they will completely cancel each other out, resulting in a net force of zero. The object will remain at rest or continue with its constant velocity.
4. Unequal magnitude opposite forces: If the two forces have different magnitudes, the resulting net force will be in the direction of the larger force. The net force will be equal to the difference between the magnitudes of the two forces.
5. Example: Let's consider an object with a force of 10 N acting to the right and a force of 5 N acting to the left. The net force will be 10 N - 5 N = 5 N to the right.
In summary, the net force is determined by summing the magnitudes of the individual forces, not by taking the difference between them.
The statement is False.
When two forces act in opposite directions on an object, the net force is determined by the sum of the magnitudes of the two forces. The net force is not the difference between the two forces.
Here's a detailed explanation:
1. Definition of net force: Net force is the vector sum of all the individual forces acting on an object. It describes the overall effect of all the forces combined.
2. Opposite forces: When two forces act in opposite directions, they cancel each other out to some extent.
3. Equal magnitude opposite forces: If the two forces have equal magnitudes, they will completely cancel each other out, resulting in a net force of zero. The object will remain at rest or continue with its constant velocity.
4. Unequal magnitude opposite forces: If the two forces have different magnitudes, the resulting net force will be in the direction of the larger force. The net force will be equal to the difference between the magnitudes of the two forces.
5. Example: Let's consider an object with a force of 10 N acting to the right and a force of 5 N acting to the left. The net force will be 10 N - 5 N = 5 N to the right.
In summary, the net force is determined by summing the magnitudes of the individual forces, not by taking the difference between them.
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.
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.
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.
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.
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.
On a body, a force of 5N is applied towards North and another force of 2N is applied towards South. Net force on the body is- a)7N
- b)3N
- c)5N
- d)2N
Correct answer is option 'B'. Can you explain this answer?
On a body, a force of 5N is applied towards North and another force of 2N is applied towards South. Net force on the body is
a)
7N
b)
3N
c)
5N
d)
2N
|
|
EduRev Class 8 answered |
When forces are applied inn the opposite directions, the forces get subtracted.
So, net force on the body = (5-2)N = 3N
So, net force on the body = (5-2)N = 3N
Why does a sharp knife enable us to cut through things more easily?- a)The pressure exerted is lesser when the same force is used
- b)The pressure exerted is greater when the same force is used
- c)The sharp edge can pass through the material slowly
- d)The sharp edge is not felt when cutting through the material
Correct answer is option 'B'. Can you explain this answer?
Why does a sharp knife enable us to cut through things more easily?
a)
The pressure exerted is lesser when the same force is used
b)
The pressure exerted is greater when the same force is used
c)
The sharp edge can pass through the material slowly
d)
The sharp edge is not felt when cutting through the material
|
Rahul Kumar answered |
The pressure is defined as the force per unit area. i.e P=F/A
So the pressure depends on the force F and area A of contact.
If force is constant, the pressure is only depends on the area.
A sharp knife edge has small area of contact and less area of contact will produce the more pressure.
Thus, the option B can be correct.
So the pressure depends on the force F and area A of contact.
If force is constant, the pressure is only depends on the area.
A sharp knife edge has small area of contact and less area of contact will produce the more pressure.
Thus, the option B can be correct.
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.
Compare the pressure exerted by a sharp needle on a surface and the pressure exerted by a blunt needle.- a)The pressure exerted by both is equal
- b)The pressure exerted by a blunt needle is more
- c)The pressure exerted by a sharp needle is more
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Compare the pressure exerted by a sharp needle on a surface and the pressure exerted by a blunt needle.
a)
The pressure exerted by both is equal
b)
The pressure exerted by a blunt needle is more
c)
The pressure exerted by a sharp needle is more
d)
None of these
|
|
Garima Chauhan answered |
Pressure Exerted by Sharp Needle vs. Blunt Needle
Pressure is defined as the force applied per unit area. When comparing the pressure exerted by a sharp needle and a blunt needle on a surface, the key factor to consider is the surface area in contact with the object.
Sharp Needle
- A sharp needle has a very small surface area in contact with the object.
- As the surface area is small, the force applied by the sharp needle is concentrated over a small area.
- This results in a higher pressure being exerted by the sharp needle on the surface.
Blunt Needle
- A blunt needle has a larger surface area in contact with the object.
- The force applied by the blunt needle is distributed over a larger area.
- Due to the larger surface area, the pressure exerted by the blunt needle on the surface is lower compared to that of a sharp needle.
Therefore, the pressure exerted by a sharp needle is more than the pressure exerted by a blunt needle. This is because the force is concentrated over a smaller area in the case of a sharp needle, resulting in higher pressure.
When we press the bulb of 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)Pressure of water
- b)Gravity of the earth
- c)Shape of rubber bulb
- d)Atmospheric pressure
Correct answer is option 'D'. Can you explain this answer?
When we press the bulb of 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)
Pressure of water
b)
Gravity of the earth
c)
Shape of rubber bulb
d)
Atmospheric pressure
|
|
EduRev Class 8 answered |
The rise of water in the dropper is due to atmospheric pressure.
When the bulb of a dropper is pressed, the pressure inside the dropper decreases and this causes the water to go inside the dropper.
When the bulb of a dropper is pressed, the pressure inside the dropper decreases and this causes the water to go inside the dropper.
Which of these is an example of a non-contact force?- a)A bar magnet moves a paperclip without touching it
- b)A toy car slides down the ramp
- c)A child lifts a book lying on the table
- d)A marble rolling on the carpet slows down
Correct answer is option 'A'. Can you explain this answer?
Which of these is an example of a non-contact force?
a)
A bar magnet moves a paperclip without touching it
b)
A toy car slides down the ramp
c)
A child lifts a book lying on the table
d)
A marble rolling on the carpet slows down
|
Riddhi Chhabra answered |
Option B,C,d
D are examples of friction force which is a contact force wherein Option A is an example of magnetic force which is a non- contact force .
D are examples of friction force which is a contact force wherein Option A is an example of magnetic force which is a non- contact force .
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.
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.
The net force on an object is zero if the two forces act on it in- a)Opposite direction
- b)Same direction
- c)Sometimes opposite and sometimes in same direction.
- d)All of above.
Correct answer is option 'A'. Can you explain this answer?
The net force on an object is zero if the two forces act on it in
a)
Opposite direction
b)
Same direction
c)
Sometimes opposite and sometimes in same direction.
d)
All of above.
|
Deepak Pillai answered |
Understanding Net Force
When discussing forces acting on an object, the net force is the vector sum of all the forces. This means that when forces are applied, they can either combine or cancel each other out, leading to different effects on the object's motion.
Conditions for Zero Net Force
For the net force on an object to be zero, the forces acting upon it must be balanced. Here are the conditions:
Conclusion
The correct answer is option 'A' because only when two forces act in opposite directions with equal strength can they result in a net force of zero. In all other scenarios, the forces will either add up or not completely cancel out, leading to a non-zero net force. Understanding these principles is crucial in physics, especially when analyzing motion and equilibrium.
When discussing forces acting on an object, the net force is the vector sum of all the forces. This means that when forces are applied, they can either combine or cancel each other out, leading to different effects on the object's motion.
Conditions for Zero Net Force
For the net force on an object to be zero, the forces acting upon it must be balanced. Here are the conditions:
- Opposite Directions: When two forces act on an object in opposite directions and are equal in magnitude, they cancel each other out. For example, if one force pulls an object to the right with 5 N and another pulls it to the left with 5 N, the net force is zero.
- Same Direction: If two forces act on an object in the same direction, they add up rather than cancel each other. For instance, two forces of 3 N and 2 N acting to the right result in a net force of 5 N to the right.
- Sometimes Opposite and Sometimes in Same Direction: If forces alternate between being in the same and opposite directions, the net force can still change depending on their magnitudes and directions. Thus, it does not guarantee that the net force is zero.
Conclusion
The correct answer is option 'A' because only when two forces act in opposite directions with equal strength can they result in a net force of zero. In all other scenarios, the forces will either add up or not completely cancel out, leading to a non-zero net force. Understanding these principles is crucial in physics, especially when analyzing motion and equilibrium.
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.
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.
At least two objects must interact for a force to come into play.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
At least two objects must interact for a force to come into play.
a)
True
b)
False
|
Ayush Unni answered |
Understanding Forces
In physics, a force is defined as an interaction that can change the motion of an object. Forces are fundamental to understanding how objects behave in our universe.
Interaction of Objects
- Definition of Force: A force is an influence that can cause an object to accelerate, decelerate, or change direction.
- Nature of Interaction: For a force to be present, at least two objects must interact. This interaction could be through contact forces (like friction or tension) or action-at-a-distance forces (like gravity or electromagnetic forces).
Examples of Forces in Action
- Contact Forces:
- When you push a box, your hand (object 1) exerts a force on the box (object 2). Both are involved in this interaction.
- Action-at-a-Distance Forces:
- The Earth and the Moon interact through gravitational force. The Earth pulls on the Moon, and the Moon pulls back on the Earth, demonstrating that both objects are essential for the gravitational force to exist.
Conclusion
In summary, the statement that "at least two objects must interact for a force to come into play" is true. Forces arise from interactions, and without multiple objects, no force can be generated. Understanding this concept is crucial in physics as it lays the foundation for the laws of motion and how we analyze physical phenomena.
In physics, a force is defined as an interaction that can change the motion of an object. Forces are fundamental to understanding how objects behave in our universe.
Interaction of Objects
- Definition of Force: A force is an influence that can cause an object to accelerate, decelerate, or change direction.
- Nature of Interaction: For a force to be present, at least two objects must interact. This interaction could be through contact forces (like friction or tension) or action-at-a-distance forces (like gravity or electromagnetic forces).
Examples of Forces in Action
- Contact Forces:
- When you push a box, your hand (object 1) exerts a force on the box (object 2). Both are involved in this interaction.
- Action-at-a-Distance Forces:
- The Earth and the Moon interact through gravitational force. The Earth pulls on the Moon, and the Moon pulls back on the Earth, demonstrating that both objects are essential for the gravitational force to exist.
Conclusion
In summary, the statement that "at least two objects must interact for a force to come into play" is true. Forces arise from interactions, and without multiple objects, no force can be generated. Understanding this concept is crucial in physics as it lays the foundation for the laws of motion and how we analyze physical phenomena.
How does the pressure exerted by a liquid change?- a)Increases with depth
- b)Decreases with depth
- c)Remains constant
- d)First increases and then decreases
Correct answer is option 'A'. Can you explain this answer?
How does the pressure exerted by a liquid change?
a)
Increases with depth
b)
Decreases with depth
c)
Remains constant
d)
First increases and then decreases
|
|
EduRev Class 8 answered |
The pressure exerted by a liquid increases with depth.
As we go we deeper in a liquid the pressure of liquid increases. As the depth of liquid increases the weight of liquid column pushing down from above increases and hence the pressure also increases.
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.
Fluid pressure comprises of which of the following pressures?- a)Air pressure
- b)Water pressure
- c)Gauge pressure
- d)Both A and B
Correct answer is option 'D'. Can you explain this answer?
Fluid pressure comprises of which of the following pressures?
a)
Air pressure
b)
Water pressure
c)
Gauge pressure
d)
Both A and B
|
|
Rahul Kumar answered |
A fluid is defined as a substance that has no fixed shape and yields easily to external pressure. They are of two kinds- Gases and Liquids.
The fluid pressure is, thus, of two kinds.
One is due to gases(air) and is called air pressure.
The other is due to liquids(water) and is called water pressure.
The fluid pressure is, thus, of two kinds.
One is due to gases(air) and is called air pressure.
The other is due to liquids(water) and is called water pressure.
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.
A force can change the state of motion of an object.- a)True
- b)False
Correct answer is option 'A'. Can you explain this answer?
A force can change the state of motion of an object.
a)
True
b)
False
|
|
Shubham Sharma answered |
If the force applied on the object is in the direction of its motion, the speed of the object increases. If the force is applied in the direction opposite to the direction of motion, then it results in a decrease in the speed of the object. Thus, a force may bring a change in the state of motion of an object.
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
|
|
Ashwin Sen answered |
Understanding Net Force
When two forces act in opposite directions on an object, it is essential to determine the net force to understand how the object will move.
What is Net Force?
- Net force is the overall force acting on an object when all individual forces are combined.
- It determines the object's acceleration and direction of motion according to Newton's Second Law of Motion.
Forces Acting in Opposite Directions
- When two forces are applied in opposite directions, they can be thought of as competing against each other.
- For instance, if one force is pushing to the right and another is pushing to the left, the net effect is determined by the difference between these two forces.
Calculating the Net Force
- To find the net force, you take the difference between the magnitudes of the two forces.
- If Force A is 5 N to the right and Force B is 3 N to the left, the net force would be calculated as follows:
- Net Force = 5 N (right) - 3 N (left) = 2 N (right)
Conclusion
- Therefore, when two forces act in opposite directions, the correct way to find the net force is by calculating the difference between the two forces (option B).
- This difference will determine the direction and magnitude of the net force acting on the object, influencing its motion effectively.
When two forces act in opposite directions on an object, it is essential to determine the net force to understand how the object will move.
What is Net Force?
- Net force is the overall force acting on an object when all individual forces are combined.
- It determines the object's acceleration and direction of motion according to Newton's Second Law of Motion.
Forces Acting in Opposite Directions
- When two forces are applied in opposite directions, they can be thought of as competing against each other.
- For instance, if one force is pushing to the right and another is pushing to the left, the net effect is determined by the difference between these two forces.
Calculating the Net Force
- To find the net force, you take the difference between the magnitudes of the two forces.
- If Force A is 5 N to the right and Force B is 3 N to the left, the net force would be calculated as follows:
- Net Force = 5 N (right) - 3 N (left) = 2 N (right)
Conclusion
- Therefore, when two forces act in opposite directions, the correct way to find the net force is by calculating the difference between the two forces (option B).
- This difference will determine the direction and magnitude of the net force acting on the object, influencing its motion effectively.
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.
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