Dive into the realm of dynamics with our extensive bank of 1000+ Dynamics MCQs, complete with explanations, ideal for Class 9 students aiming to master forces, motion, and Newton’s laws.

## 100+ Dynamics MCQs with Explanations for Class 9

Delve into the principles of Dynamics through our comprehensive bank of MCQs. With over 100+ MCQs designed for Class 9 students, this resource offers in-depth exploration of forces, motion, and Newton’s laws, facilitating a thorough grasp of the subject.

- Which of the following best describes inertia?

A) The tendency of an object to resist a change in its state of motion

B) The force applied on an object to change its motion

C) The velocity of an object

D) The mass of an object

Explanation: Inertia is the property of matter by which it retains its state of rest or uniform motion unless acted upon by an external force. Option A correctly describes this property. - What is momentum?

A) The force exerted by an object

B) The product of an object’s mass and velocity

C) The resistance of an object to change its motion

D) The force required to change an object’s momentum

Explanation: Momentum is the product of an object’s mass and velocity. Therefore, option B is correct. - According to Newton’s first law of motion, an object will continue its state of rest or uniform motion unless acted upon by:

A) A force

B) Gravity

C) Friction

D) Momentum

Explanation: Newton’s first law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. Thus, option A is correct. - What is the SI unit of force?

A) Joule

B) Watt

C) Newton

D) Pascal

Explanation: The SI unit of force is the Newton (N), named after Sir Isaac Newton. Option C is correct. - Which of the following statements best describes Newton’s second law of motion?

A) An object in motion will stay in motion unless acted upon by an external force.

B) Force equals mass times acceleration.

C) For every action, there is an equal and opposite reaction.

D) The rate of change of momentum of an object is directly proportional to the force applied and in the direction of the force.

Explanation: Newton’s second law states that force equals mass times acceleration (F = ma). Hence, option B is correct. - If the mass of an object increases, what happens to its acceleration under a constant force?

A) Increases

B) Decreases

C) Remains the same

D) Cannot be determined

Explanation: According to Newton’s second law (F = ma), if force remains constant and mass increases, acceleration decreases. So, option B is correct. - What is the relationship between force and momentum?

A) Force is directly proportional to momentum

B) Force is inversely proportional to momentum

C) Force is equal to momentum

D) There is no relationship between force and momentum

Explanation: Force is directly proportional to the rate of change of momentum, as per Newton’s second law. So, option A is correct. - Which of the following statements is true regarding the law of conservation of momentum?

A) The total momentum of a closed system remains constant if no external forces act on it.

B) Momentum is lost when two objects collide.

C) Momentum increases with time in an isolated system.

D) Momentum is inversely proportional to mass.

Explanation: The law of conservation of momentum states that the total momentum of a closed system remains constant if no external forces act on it. Thus, option A is correct. - What is friction?

A) The force applied to an object to move it

B) The force that opposes motion between surfaces that are in contact

C) The force of gravity acting on an object

D) The force exerted by an object in motion

Explanation: Friction is the force that opposes motion between surfaces in contact. So, option B is correct. - Which of the following is an example of rolling friction?

A) A car sliding on a wet road

B) A sled sliding down a snow-covered hill

C) A ball rolling on the ground

D) A person walking on a rough surface

Explanation: Rolling friction occurs when an object rolls over a surface, such as a ball rolling on the ground. Therefore, option C is correct. - When a car comes to a stop due to friction between its tires and the road surface, it is an example of:

A) Static friction

B) Sliding friction

C) Rolling friction

D) Fluid friction

Explanation: When the car stops, the friction between its tires and the road surface is static friction. So, option A is correct. - Which of the following methods can reduce friction between moving parts?

A) Increasing the surface roughness

B) Lubricating the surfaces

C) Adding weight to the objects

D) Tightening the contact between surfaces

Explanation: Lubricating the surfaces reduces friction between moving parts by providing a slippery layer. Thus, option B is correct. - What is the centripetal force?

A) The force that pushes an object outward during circular motion

B) The force that pulls an object toward the center of a circle during circular motion

C) The force that maintains an object’s velocity during circular motion

D) The force that opposes motion in a straight line

Explanation: The centripetal force is the force that pulls an object toward the center of a circle during circular motion. So, option B is correct. - In uniform circular motion, what provides the centripetal force?

A) Gravity

B) Friction

C) Tension in the string

D) Normal force

Explanation: In uniform circular motion, the centripetal force is provided by tension in the string or any other force directed toward the center of the circle. So, option C is correct. - What is the centrifugal force?

A) The force that pushes an object outward during circular motion

B) The force that pulls an object toward the center of a circle during circular motion

C) The force that maintains an object’s velocity during circular motion

D) The force that opposes motion in a straight line

Explanation: The centrifugal force is the apparent outward force experienced by an object moving in a circular path, but it is not a real force. Option A is correct. - What causes banking of roads on curved paths?

A) Friction

B) Centrifugal force

C) Centripetal force

D) Gravity

Explanation: Banking of roads is caused by the centripetal force, which is directed toward the center of the curve. So, option C is correct. - Which of the following devices utilizes centrifugal force to separate substances of different densities?

A) Washing machine dryer

B) Cream separator

C) Air conditioner

D) Blender

Explanation: A cream separator utilizes centrifugal force to separate substances of different densities, such as cream from milk. Option B is correct. - Which of the following represents Newton’s third law of motion?

A) “Every action has an equal and opposite reaction.”

B) “An object in motion will stay in motion unless acted upon by an external force.”

C) “Force equals mass times acceleration.”

D) “An object will continue its state of rest or uniform motion unless acted upon by a force.”

Explanation: Newton’s third law states that for every action, there is an equal and opposite reaction. Thus, option A is correct. - What is weight?

A) The force exerted by an object

B) The mass of an object

C) The resistance of an object to change its motion

D) The gravitational force exerted on an object

Explanation: Weight is the gravitational force exerted on an object, so option D is correct. - If the mass of an object remains constant, what happens to its weight when it is taken to the moon’s surface?

A) Increases

B) Decreases

C) Remains the same

D) Becomes zero

Explanation: Weight depends on the gravitational pull exerted on the object, so when taken to the moon’s surface, it decreases due to the moon’s weaker gravitational pull. Thus, option B is correct. - What is the formula to calculate momentum?

A)

B)

C)

D)

Explanation: Momentum (p) is calculated using the formula , where m is mass and v is velocity. So, option A is correct. - If a force of 10N is applied to an object with a mass of 5kg, what is its acceleration?

A) 2 m/s^2

B) 5 m/s^2

C) 50 m/s^2

D) 15 m/s^2

Explanation: Using Newton’s second law (F = ma), acceleration (a) can be calculated as . Substituting the given values, we get m/s^2. So, option A is correct. - Which of the following statements is true regarding the law of conservation of momentum?

A) The total momentum of a closed system remains constant if no external forces act on it.

B) Momentum is lost when two objects collide.

C) Momentum increases with time in an isolated system.

D) Momentum is inversely proportional to mass.

Explanation: The law of conservation of momentum states that the total momentum of a closed system remains constant if no external forces act on it. Thus, option A is correct. - What is the unit of frictional force?

A) Newton (N)

B) Joule (J)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: Frictional force is measured in Newtons (N). So, option A is correct. - How does friction affect the motion of an object on an inclined plane?

A) Increases the motion

B) Decreases the motion

C) Does not affect the motion

D) Changes the direction of motion

Explanation: Friction opposes the motion of the object, so it decreases the motion on an inclined plane. Therefore, option B is correct. - What is the minimum force required to keep an object moving in a circular path?

A) Centrifugal force

B) Centripetal force

C) Frictional force

D) Tension force

Explanation: The minimum force required to keep an object moving in a circular path is the centripetal force, directed toward the center of the circle. So, option B is correct. - Which of the following is an example of rolling friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A car skidding on a wet road

Explanation: Rolling friction occurs when an object rolls over a surface, like a ball rolling on the ground. Therefore, option B is correct. - What is the relationship between mass and weight?

A) Mass and weight are the same.

B) Mass is directly proportional to weight.

C) Mass is inversely proportional to weight.

D) Mass and weight are unrelated.

Explanation: Mass is the amount of matter in an object, whereas weight is the force of gravity acting on that object. They are not the same; however, weight is directly proportional to mass. Therefore, option B is correct. - What is the SI unit of momentum?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Kilogram meter per second (kg m/s)

Explanation: The SI unit of momentum is kilogram meter per second (kg m/s). Thus, option D is correct. - How does friction between the tires and the road help a car to move forward?

A) By reducing the friction

B) By increasing the friction

C) By eliminating the friction

D) By changing the direction of friction

Explanation: Friction between the tires and the road helps a car move forward by increasing traction and preventing slipping. Therefore, option B is correct. - Which of the following factors affect the frictional force between two surfaces?

A) Surface area and weight of the object

B) Surface roughness and weight of the object

C) Surface area and velocity of the object

D) Surface roughness and velocity of the object

Explanation: Surface roughness and the weight of the object are factors that affect the frictional force between two surfaces. So, option B is correct. - What is the effect of increasing the mass of an object on its inertia?

A) Increases the inertia

B) Decreases the inertia

C) Does not affect the inertia

D) Changes the direction of inertia

Explanation: Inertia is directly proportional to mass, so increasing the mass of an object increases its inertia. Thus, option A is correct. - Which of the following is true about the relationship between mass and weight?

A) Weight depends on mass.

B) Mass depends on weight.

C) Mass and weight are independent of each other.

D) Weight is a measure of mass.

Explanation: Weight depends on mass and the acceleration due to gravity. Thus, option A is correct. - What is the net force acting on an object in equilibrium?

A) Zero

B) Non-zero

C) Cannot be determined

D) Depends on the mass of the object

Explanation: In equilibrium, the net force acting on an object is zero. Thus, option A is correct. - Which of the following best describes Newton’s first law of motion?

A) An object will continue its state of rest or uniform motion unless acted upon by an external force.

B) Force equals mass times acceleration.

C) For every action, there is an equal and opposite reaction.

D) The rate of change of momentum of an object is directly proportional to the force applied and in the direction of the force.

Explanation: Newton’s first law states that an object will remain at rest or in uniform motion unless acted upon by an external force. Thus, option A is correct. - What is the SI unit of weight?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Meter per second squared (m/s^2)

Explanation: The SI unit of weight is the Newton (N). So, option A is correct. - How does mass affect the inertia of an object?

A) Mass has no effect on inertia.

B) More mass results in less inertia.

C) More mass results in more inertia.

D) Inertia is inversely proportional to mass.

Explanation: Inertia is directly proportional to mass, so more mass results in more inertia. Therefore, option C is correct. - Which of the following is a disadvantage of friction?

A) Helps in walking

B) Causes wear and tear of machinery

C) Helps in writing

D) Aids in stopping vehicles

Explanation: Friction causes wear and tear of machinery, which is a disadvantage. So, option B is correct. - Which of the following is an example of sliding friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A person sliding down a slide

Explanation: Sliding friction occurs when two surfaces slide past each other, as in a person sliding down a slide. Thus, option D is correct. - What is the unit of acceleration?

A) Newton (N)

B) Kilogram (kg)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The unit of acceleration is meter per second squared (m/s^2). So, option C is correct. - What happens to the momentum of an object if its velocity is doubled?

A) Momentum is halved

B) Momentum remains the same

C) Momentum is doubled

D) Momentum is quadrupled

Explanation: Momentum is directly proportional to velocity, so if velocity is doubled, momentum is also doubled. Thus, option C is correct. - Which of the following is an example of circular motion?

A) A car moving in a straight line

B) A merry-go-round rotating about its axis

C) A ball thrown upward

D) A person walking on a road

Explanation: A merry-go-round rotating about its axis is an example of circular motion. So, option B is correct. - Which of the following is true regarding frictional force?

A) It always opposes motion.

B) It always aids motion.

C) It only occurs between solids.

D) It is not affected by the surface roughness.

Explanation: Frictional force always opposes motion between surfaces in contact. Therefore, option A is correct. - How does increasing the mass of an object affect its momentum?

A) Increases the momentum

B) Decreases the momentum

C) Does not affect the momentum

D) Changes the direction of momentum

Explanation: Momentum is directly proportional to mass, so increasing the mass of an object increases its momentum. Thus, option A is correct. - Which of the following best describes Newton’s third law of motion?

A) “Every action has an equal and opposite reaction.”

B) “An object in motion will stay in motion unless acted upon by an external force.”

C) “Force equals mass times acceleration.”

D) “An object will continue its state of rest or uniform motion unless acted upon by a force.”

Explanation: Newton’s third law states that for every action, there is an equal and opposite reaction. Thus, option A is correct. - What is the SI unit of friction?

A) Newton (N)

B) Joule (J)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The SI unit of friction is the Newton (N). So, option A is correct. - How does friction affect the motion of an object on an inclined plane?

A) Increases the motion

B) Decreases the motion

C) Does not affect the motion

D) Changes the direction of motion

Explanation: Friction opposes the motion of the object, so it decreases the motion on an inclined plane. Therefore, option B is correct. - What is the minimum force required to keep an object moving in a circular path?

A) Centrifugal force

B) Centripetal force

C) Frictional force

D) Tension force

Explanation: The minimum force required to keep an object moving in a circular path is the centripetal force, directed toward the center of the circle. So, option B is correct. - Which of the following is an example of rolling friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A car skidding on a wet road

Explanation: Rolling friction occurs when an object rolls over a surface, like a ball rolling on the ground. Therefore, option B is correct. - What is the relationship between mass and weight?

A) Mass and weight are the same.

B) Mass is directly proportional to weight.

C) Mass is inversely proportional to weight.

D) Mass and weight are unrelated.

Explanation: Mass is the amount of matter in an object, whereas weight is the force of gravity acting on that object. They are not the same; however, weight is directly proportional to mass. Therefore, option B is correct. - What is the SI unit of momentum?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Kilogram meter per second (kg m/s)

Explanation: The SI unit of momentum is kilogram meter per second (kg m/s). Thus, option D is correct. - How does friction between the tires and the road help a car to move forward?

A) By reducing the friction

B) By increasing the friction

C) By eliminating the friction

D) By changing the direction of friction

Explanation: Friction between the tires and the road helps a car move forward by increasing traction and preventing slipping. Therefore, option B is correct. - Which of the following factors affect the frictional force between two surfaces?

A) Surface area and weight of the object

B) Surface roughness and weight of the object

C) Surface area and velocity of the object

D) Surface roughness and velocity of the object

Explanation: Surface roughness and the weight of the object are factors that affect the frictional force between two surfaces. So, option B is correct. - What is the effect of increasing the mass of an object on its inertia?

A) Increases the inertia

B) Decreases the inertia

C) Does not affect the inertia

D) Changes the direction of inertia

Explanation: Inertia is directly proportional to mass, so increasing the mass of an object increases its inertia. Thus, option A is correct. - Which of the following is true about the relationship between mass and weight?

A) Weight depends on mass.

B) Mass depends on weight.

C) Mass and weight are independent of each other.

D) Weight is a measure of mass.

Explanation: Weight depends on mass and the acceleration due to gravity. Thus, option A is correct. - What is the net force acting on an object in equilibrium?

A) Zero

B) Non-zero

C) Cannot be determined

D) Depends on the mass of the object

Explanation: In equilibrium, the net force acting on an object is zero. Thus, option A is correct. - Which of the following best describes Newton’s first law of motion?

A) An object will continue its state of rest or uniform motion unless acted upon by an external force.

B) Force equals mass times acceleration.

C) For every action, there is an equal and opposite reaction.

D) The rate of change of momentum of an object is directly proportional to the force applied and in the direction of the force.

Explanation: Newton’s first law states that an object will remain at rest or in uniform motion unless acted upon by an external force. Thus, option A is correct. - What is the SI unit of weight?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Meter per second squared (m/s^2)

Explanation: The SI unit of weight is the Newton (N). So, option A is correct. - How does mass affect the inertia of an object?

A) Mass has no effect on inertia.

B) More mass results in less inertia.

C) More mass results in more inertia.

D) Inertia is inversely proportional to mass.

Explanation: Inertia is directly proportional to mass, so more mass results in more inertia. Therefore, option C is correct. - Which of the following is a disadvantage of friction?

A) Helps in walking

B) Causes wear and tear of machinery

C) Helps in writing

D) Aids in stopping vehicles

Explanation: Friction causes wear and tear of machinery, which is a disadvantage. So, option B is correct. - Which of the following is an example of sliding friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A person sliding down a slide

Explanation: Sliding friction occurs when two surfaces slide past each other, as in a person sliding down a slide. Thus, option D is correct. - What is the unit of acceleration?

A) Newton (N)

B) Kilogram (kg)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The unit of acceleration is meter per second squared (m/s^2). So, option C is correct. - What happens to the momentum of an object if its velocity is doubled?

A) Momentum is halved

B) Momentum remains the same

C) Momentum is doubled

D) Momentum is quadrupled

Explanation: Momentum is directly proportional to velocity, so if velocity is doubled, momentum is also doubled. Thus, option C is correct. - Which of the following is an example of circular motion?

A) A car moving in a straight line

B) A merry-go-round rotating about its axis

C) A ball thrown upward

D) A person walking on a road

Explanation: A merry-go-round rotating about its axis is an example of circular motion. So, option B is correct. - Which of the following is true regarding frictional force?

A) It always opposes motion.

B) It always aids motion.

C) It only occurs between solids.

D) It is not affected by the surface roughness.

Explanation: Frictional force always opposes motion between surfaces in contact. Therefore, option A is correct. - How does increasing the mass of an object affect its momentum?

A) Increases the momentum

B) Decreases the momentum

C) Does not affect the momentum

D) Changes the direction of momentum

Explanation: Momentum is directly proportional to mass, so increasing the mass of an object increases its momentum. Thus, option A is correct. - Which of the following best describes Newton’s third law of motion?

A) “Every action has an equal and opposite reaction.”

B) “An object in motion will stay in motion unless acted upon by an external force.”

C) “Force equals mass times acceleration.”

D) “An object will continue its state of rest or uniform motion unless acted upon by a force.”

Explanation: Newton’s third law states that for every action, there is an equal and opposite reaction. Thus, option A is correct. - What is the SI unit of friction?

A) Newton (N)

B) Joule (J)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The SI unit of friction is the Newton (N). So, option A is correct. - How does friction affect the motion of an object on an inclined plane?

A) Increases the motion

B) Decreases the motion

C) Does not affect the motion

D) Changes the direction of motion

Explanation: Friction opposes the motion of the object, so it decreases the motion on an inclined plane. Therefore, option B is correct. - What is the minimum force required to keep an object moving in a circular path?

A) Centrifugal force

B) Centripetal force

C) Frictional force

D) Tension force

Explanation: The minimum force required to keep an object moving in a circular path is the centripetal force, directed toward the center of the circle. So, option B is correct. - Which of the following is an example of rolling friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A car skidding on a wet road

Explanation: Rolling friction occurs when an object rolls over a surface, like a ball rolling on the ground. Therefore, option B is correct. - What is the relationship between mass and weight?

A) Mass and weight are the same.

B) Mass is directly proportional to weight.

C) Mass is inversely proportional to weight.

D) Mass and weight are unrelated.

Explanation: Mass is the amount of matter in an object, whereas weight is the force of gravity acting on that object. They are not the same; however, weight is directly proportional to mass. Therefore, option B is correct. - What is the SI unit of momentum?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Kilogram meter per second (kg m/s)

Explanation: The SI unit of momentum is kilogram meter per second (kg m/s). Thus, option D is correct. - How does friction between the tires and the road help a car to move forward?

A) By reducing the friction

B) By increasing the friction

C) By eliminating the friction

D) By changing the direction of friction

Explanation: Friction between the tires and the road helps a car move forward by increasing traction and preventing slipping. Therefore, option B is correct. - Which of the following factors affect the frictional force between two surfaces?

A) Surface area and weight of the object

B) Surface roughness and weight of the object

C) Surface area and velocity of the object

D) Surface roughness and velocity of the object

Explanation: Surface roughness and the weight of the object are factors that affect the frictional force between two surfaces. So, option B is correct. - What is the effect of increasing the mass of an object on its inertia?

A) Increases the inertia

B) Decreases the inertia

C) Does not affect the inertia

D) Changes the direction of inertia

Explanation: Inertia is directly proportional to mass, so increasing the mass of an object increases its inertia. Thus, option A is correct. - Which of the following is true about the relationship between mass and weight?

A) Weight depends on mass.

B) Mass depends on weight.

C) Mass and weight are independent of each other.

D) Weight is a measure of mass.

Explanation: Weight depends on mass and the acceleration due to gravity. Thus, option A is correct. - What is the net force acting on an object in equilibrium?

A) Zero

B) Non-zero

C) Cannot be determined

D) Depends on the mass of the object

Explanation: In equilibrium, the net force acting on an object is zero. Thus, option A is correct. - Which of the following best describes Newton’s first law of motion?

A) An object will continue its state of rest or uniform motion unless acted upon by an external force.

B) Force equals mass times acceleration.

C) For every action, there is an equal and opposite reaction.

D) The rate of change of momentum of an object is directly proportional to the force applied and in the direction of the force.

Explanation: Newton’s first law states that an object will remain at rest or in uniform motion unless acted upon by an external force. Thus, option A is correct. - What is the SI unit of weight?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Meter per second squared (m/s^2)

Explanation: The SI unit of weight is the Newton (N). So, option A is correct. - How does mass affect the inertia of an object?

A) Mass has no effect on inertia.

B) More mass results in less inertia.

C) More mass results in more inertia.

D) Inertia is inversely proportional to mass.

Explanation: Inertia is directly proportional to mass, so more mass results in more inertia. Therefore, option C is correct. - Which of the following is a disadvantage of friction?

A) Helps in walking

B) Causes wear and tear of machinery

C) Helps in writing

D) Aids in stopping vehicles

Explanation: Friction causes wear and tear of machinery, which is a disadvantage. So, option B is correct. - Which of the following is an example of sliding friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A person sliding down a slide

Explanation: Sliding friction occurs when two surfaces slide past each other, as in a person sliding down a slide. Thus, option D is correct. - What is the unit of acceleration?

A) Newton (N)

B) Kilogram (kg)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The unit of acceleration is meter per second squared (m/s^2). So, option C is correct. - What happens to the momentum of an object if its velocity is doubled?

A) Momentum is halved

B) Momentum remains the same

C) Momentum is doubled

D) Momentum is quadrupled

Explanation: Momentum is directly proportional to velocity, so if velocity is doubled, momentum is also doubled. Thus, option C is correct. - Which of the following is an example of circular motion?

A) A car moving in a straight line

B) A merry-go-round rotating about its axis

C) A ball thrown upward

D) A person walking on a road

Explanation: A merry-go-round rotating about its axis is an example of circular motion. So, option B is correct. - Which of the following is true regarding frictional force?

A) It always opposes motion.

B) It always aids motion.

C) It only occurs between solids.

D) It is not affected by the surface roughness.

Explanation: Frictional force always opposes motion between surfaces in contact. Therefore, option A is correct. - How does increasing the mass of an object affect its momentum?

A) Increases the momentum

B) Decreases the momentum

C) Does not affect the momentum

D) Changes the direction of momentum

Explanation: Momentum is directly proportional to mass, so increasing the mass of an object increases its momentum. Thus, option A is correct. - Which of the following best describes Newton’s third law of motion?

A) “Every action has an equal and opposite reaction.”

B) “An object in motion will stay in motion unless acted upon by an external force.”

C) “Force equals mass times acceleration.”

D) “An object will continue its state of rest or uniform motion unless acted upon by a force.”

Explanation: Newton’s third law states that for every action, there is an equal and opposite reaction. Thus, option A is correct. - What is the SI unit of friction?

A) Newton (N)

B) Joule (J)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The SI unit of friction is the Newton (N). So, option A is correct. - How does friction affect the motion of an object on an inclined plane?

A) Increases the motion

B) Decreases the motion

C) Does not affect the motion

D) Changes the direction of motion

Explanation: Friction opposes the motion of the object, so it decreases the motion on an inclined plane. Therefore, option B is correct. - What is the minimum force required to keep an object moving in a circular path?

A) Centrifugal force

B) Centripetal force

C) Frictional force

D) Tension force

Explanation: The minimum force required to keep an object moving in a circular path is the centripetal force, directed toward the center of the circle. So, option B is correct. - Which of the following is an example of rolling friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A car skidding on a wet road Explanation: Rolling friction occurs when an object rolls over a surface, like a ball rolling on the ground. Therefore, option B is correct. - What is the relationship between mass and weight?

A) Mass and weight are the same.

B) Mass is directly proportional to weight.

C) Mass is inversely proportional to weight.

D) Mass and weight are unrelated.

Explanation: Mass is the amount of matter in an object, whereas weight is the force of gravity acting on that object. They are not the same; however, weight is directly proportional to mass. Therefore, option B is correct. - What is the SI unit of momentum?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Kilogram meter per second (kg m/s)

Explanation: The SI unit of momentum is kilogram meter per second (kg m/s). Thus, option D is correct. - How does friction between the tires and the road help a car to move forward?

A) By reducing the friction

B) By increasing the friction

C) By eliminating the friction

D) By changing the direction of friction Explanation: Friction between the tires and the road helps a car move forward by increasing traction and preventing slipping. Therefore, option B is correct. - Which of the following factors affect the frictional force between two surfaces?

A) Surface area and weight of the object

B) Surface roughness and weight of the object

C) Surface area and velocity of the object

D) Surface roughness and velocity of the object

Explanation: Surface roughness and the weight of the object are factors that affect the frictional force between two surfaces. So, option B is correct. - What is the effect of increasing the mass of an object on its inertia?

A) Increases the inertia

B) Decreases the inertia

C) Does not affect the inertia

D) Changes the direction of inertia

Explanation: Inertia is directly proportional to mass, so increasing the mass of an object increases its inertia. Thus, option A is correct. - Which of the following is true about the relationship between mass and weight?

A) Weight depends on mass.

B) Mass depends on weight.

C) Mass and weight are independent of each other.

D) Weight is a measure of mass.

Explanation: Weight depends on mass and the acceleration due to gravity. Thus, option A is correct. - What is the net force acting on an object in equilibrium?

A) Zero

B) Non-zero

C) Cannot be determined

D) Depends on the mass of the object

Explanation: In equilibrium, the net force acting on an object is zero. Thus, option A is correct. - Which of the following best describes Newton’s first law of motion?

A) An object will continue its state of rest or uniform motion unless acted upon by an external force.

B) Force equals mass times acceleration.

C) For every action, there is an equal and opposite reaction.

D) The rate of change of momentum of an object is directly proportional to the force applied and in the direction of the force.

Explanation: Newton’s first law states that an object will remain at rest or in uniform motion unless acted upon by an external force. Thus, option A is correct. - What is the SI unit of weight?

A) Newton (N)

B) Kilogram (kg)

C) Joule (J)

D) Meter per second squared (m/s^2)

Explanation: The SI unit of weight is the Newton (N). So, option A is correct. - How does mass affect the inertia of an object?

A) Mass has no effect on inertia.

B) More mass results in less inertia.

C) More mass results in more inertia.

D) Inertia is inversely proportional to mass.

Explanation: Inertia is directly proportional to mass, so more mass results in more inertia. Therefore, option C is correct. - Which of the following is a disadvantage of friction?

A) Helps in walking

B) Causes wear and tear of machinery

C) Helps in writing

D) Aids in stopping vehicles

Explanation: Friction causes wear and tear of machinery, which is a disadvantage. So, option B is correct. - Which of the following is an example of sliding friction?

A) Ice skating

B) A ball rolling on the ground

C) A sled sliding on snow

D) A person sliding down a slide

Explanation: Sliding friction occurs when two surfaces slide past each other, as in a person sliding down a slide. Thus, option D is correct. - What is the unit of acceleration?

A) Newton (N)

B) Kilogram (kg)

C) Meter per second squared (m/s^2)

D) Pascal (Pa)

Explanation: The unit of acceleration is meter per second squared (m/s^2). So, option C is correct. - What happens to the momentum of an object if its velocity is doubled?

A) Momentum is halved

B) Momentum remains the same

C) Momentum is doubled

D) Momentum is quadrupled

Explanation: Momentum is directly proportional to velocity, so if velocity is doubled, momentum is also doubled. Thus, option C is correct. - Which of the following is an example of circular motion?

A) A car moving in a straight line

B) A merry-go-round rotating about its axis

C) A ball thrown upward

D) A person walking on a road

Explanation: A merry-go-round rotating about its axis is an example of circular motion. So, option B is correct. - Which of the following is true regarding frictional force?

A) It always opposes motion.

B) It always aids motion.

C) It only occurs between solids.

D) It is not affected by the surface roughness.

Explanation: Frictional force always opposes motion between surfaces in contact. Therefore, option A is correct. - How does increasing the mass of an object affect its momentum?

A) Increases the momentum

B) Decreases the momentum

C) Does not affect the momentum

D) Changes the direction of momentum

Explanation: Momentum is directly proportional to mass, so increasing the mass of an object increases its momentum. Thus, option A is correct.

## Physics Class 9 MCQs Chapter wise

Delve into specialized segments housing Class 9 Physics MCQs, systematically sorted by subject for convenient browsing and focused revision. Each chapter boasts over 1000 MCQs, offering ample chances to refine understanding and ace Physics concepts. Access MCQs pertaining to each segment by simply tapping on the associated chapter titles provided.

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