Friction MCQ Class 8

Q: What is friction?

Friction is the force that opposes the relative motion between two surfaces in contact.

Q: What are the factors affecting friction?

The factors affecting friction are the nature of the surfaces in contact, the state of smoothness of those surfaces, and how hard the two surfaces press together.

Q: What are the types of friction?

Static friction, Sliding friction and Rolling friction

Q: What are the ways to increase friction?

Friction can be increased by making a surface rough. For example, the soles of shoes and the tires of vehicles are patterned to increase friction.

Q: What are the ways to reduce friction?

Friction can be reduced by using lubricants or by using ball bearings.

Question 1

Question 1: What is friction?

A. A force that helps objects move fasterB. A force that opposes motion between two surfaces in contactC. A force that causes objects to float in waterD. A force that makes objects heavier

Answer

B. A force that opposes motion between two surfaces in contact. This is the basic definition of friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 2

Question 2: Which of the following is an example of friction in action?

A. A bird flying in the skyB. A fish swimming in a lakeC. A ball rolling on the ground and slowing downD. A plant growing towards the sunlight

Answer

C. A ball rolling on the ground and slowing down. Friction acts against the ball’s motion, causing it to slow down and eventually stop. (Friction MCQ Class 8 by Top100MCQ.com)

Question 3

Question 3: What do you call the force that opposes the motion of a book sliding across a table?

A. GravityB. MagnetismC. FrictionD. Inertia

Answer

C. Friction. Friction is the force that resists the sliding motion of the book. (Friction MCQ Class 8 by Top100MCQ.com)

Question 4

Question 4: Imagine pushing a toy car across a carpet. Which force is working against the car’s movement?

A. FrictionB. GravityC. WindD. Magnetism

Answer

A. Friction. The carpet’s surface creates friction against the car’s wheels, slowing it down. (Friction MCQ Class 8 by Top100MCQ.com)

Question 5

Question 5: In which direction does the force of friction act compared to the direction of motion?

A. In the same directionB. In the opposite directionC. Perpendicular to the direction of motionD. At a 45-degree angle to the direction of motion

Answer

B. In the opposite direction. Friction always acts to oppose the motion of an object. (Friction MCQ Class 8 by Top100MCQ.com)

Question 6

Question 6: Friction occurs when two surfaces have what kind of motion?

A. No motionB. Relative motionC. Only upward motionD. Only downward motion

Answer

B. Relative motion. Friction arises when surfaces slide or try to slide against each other. (Friction MCQ Class 8 by Top100MCQ.com)

Question 7

Question 7: How can we generally measure the force of friction?

A. By measuring the weight of the objectB. By measuring the speed of the objectC. By measuring the force required to initiate or maintain motionD. By measuring the temperature of the object

Answer

C. By measuring the force required to initiate or maintain motion. The force needed to overcome friction is a measure of the friction itself. (Friction MCQ Class 8 by Top100MCQ.com)

Question 8

Question 8: What happens to the frictional force if you push a heavier object?

A. It decreasesB. It remains the sameC. It increasesD. It disappears completely

Answer

C. It increases. A heavier object presses down with more force, leading to increased friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 9

Question 9: Which instrument is commonly used to measure force, including friction?

A. ThermometerB. RulerC. Spring balanceD. Stopwatch

Answer

C. Spring balance. A spring balance measures the force required to move an object against friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 10

Question 10: What principle does a spring balance use to measure force?

A. The extension of a spring is proportional to the force applied.B. The temperature of a spring changes with the force applied.C. The color of a spring changes with the force applied.D. The weight of a spring changes with the force applied.

Answer

A. The extension of a spring is proportional to the force applied. This principle allows the spring balance to accurately measure the force. (Friction MCQ Class 8 by Top100MCQ.com)

Question 11

Question 11: Which surface would generally create more friction against a moving object?

A. Smooth glassB. A rough roadC. Polished iceD. Calm water

Answer

B. A rough road. Rough surfaces have more irregularities that create friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 12

Question 12: Why does a book slide more easily on a polished tabletop than on a rough carpet?

A. The tabletop is heavier than the carpetB. The tabletop has less friction than the carpetC. The tabletop is colder than the carpetD. The tabletop is larger than the carpet

Answer

B. The tabletop has less friction than the carpet. Polished surfaces offer less resistance to motion. (Friction MCQ Class 8 by Top100MCQ.com)

Question 13

Question 13: Which of the following is an example of increasing friction intentionally?

A. Oiling a door hingeB. Adding wheels to a suitcaseC. Spreading sand on a slippery roadD. Waxing a car

Answer

C. Spreading sand on a slippery road. The sand increases the roughness and thus the friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 14

Question 14: How does the smoothness of surfaces affect friction?

A. Smoother surfaces have more frictionB. Smoother surfaces have less frictionC. Smoothness does not affect frictionD. Smoother surfaces only have static friction

Answer

B. Smoother surfaces have less friction. Fewer irregularities mean less interlocking and less friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 15

Question 15: If we make a surface extremely smooth, what happens to the friction?

A. It becomes extremely largeB. It remains the sameC. It is reduced significantlyD. It becomes zero

Answer

C. It is reduced significantly. While complete elimination is impossible, smoothing greatly reduces friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 16

Question 16: What causes friction at the microscopic level?

A. The color of the surfacesB. The temperature of the surfacesC. The interlocking of surface irregularitiesD. The weight of the objects

Answer

C. The interlocking of surface irregularities. Even seemingly smooth surfaces have tiny bumps and grooves that catch on each other. (Friction MCQ Class 8 by Top100MCQ.com)

Question 17

Question 17: Imagine two surfaces rubbing against each other. What would happen to friction if these surfaces have more irregularities?

A. Friction would decreaseB. Friction would increaseC. Friction would stay the sameD. Friction would become zero

Answer

B. Friction would increase. More irregularities mean more interlocking and greater resistance to motion. (Friction MCQ Class 8 by Top100MCQ.com)

Question 18

Question 18: What happens to the force of friction when you press two surfaces together harder?

A. It decreasesB. It stays the sameC. It increasesD. It disappears

Answer

C. It increases. Pressing harder increases the contact between irregularities, leading to higher friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 19

Question 19: Why is it harder to push a heavy box across the floor than a light one?

A. The heavy box has more gravityB. The heavy box has more frictionC. The heavy box has more air resistanceD. The heavy box has more magnetism

Answer

B. The heavy box has more friction. Its weight presses it harder against the floor, increasing friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 20

Question 20: Does friction depend on the types of surfaces in contact?

A. No, friction is the same for all surfacesB. Yes, rougher surfaces create more frictionC. Yes, smoother surfaces create more frictionD. No, the nature of the surfaces does not matter

Answer

B. Yes, rougher surfaces create more friction. Different materials and textures have varying degrees of friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 21

Question 21: Why is it harder to walk on ice than on a dry road?

A. Ice is colder than the roadB. Ice is smoother than the road, offering less frictionC. Ice is wetter than the roadD. Ice is harder than the road

Answer

B. Ice is smoother than the road, offering less friction. The reduced friction makes it difficult to get a grip and walk safely. (Friction MCQ Class 8 by Top100MCQ.com)

Question 22

Question 22: What type of friction prevents an object from moving when a force is first applied?

A. Sliding frictionB. Rolling frictionC. Static frictionD. Fluid friction

Answer

C. Static friction. Static friction is the initial resistance that needs to be overcome to start an object moving. (Friction MCQ Class 8 by Top100MCQ.com)

Question 23

Question 23: Imagine trying to push a heavy box. You apply a small force, but it doesn’t move. What kind of friction is acting on the box?

A. Rolling frictionB. Sliding frictionC. Static frictionD. No friction

Answer

C. Static friction. The static friction is strong enough to prevent the box from moving initially. (Friction MCQ Class 8 by Top100MCQ.com)

Question 24

Question 24: Which type of friction is usually the highest?

A. Sliding frictionB. Rolling frictionC. Static frictionD. They are all the same

Answer

C. Static friction. It generally takes more force to overcome static friction and start an object moving than to keep it moving. (Friction MCQ Class 8 by Top100MCQ.com)

Question 25

Question 25: What happens to static friction once an object starts moving?

A. It increasesB. It stays the sameC. It is replaced by sliding frictionD. It disappears

Answer

C. It is replaced by sliding friction. Once the object is in motion, sliding friction takes over. (Friction MCQ Class 8 by Top100MCQ.com)

Question 26

Question 26: What type of friction acts on an object sliding over a surface?

A. Static frictionB. Rolling frictionC. Sliding frictionD. Fluid friction

Answer

C. Sliding friction. This friction occurs while the object is in motion, sliding against the surface. (Friction MCQ Class 8 by Top100MCQ.com)

Question 27

Question 27: Which type of friction is generally less than static friction?

A. Rolling frictionB. Sliding frictionC. They are usually the sameD. Static friction is always less than sliding friction

Answer

B. Sliding friction. It’s usually easier to keep an object moving than to start it moving from rest. (Friction MCQ Class 8 by Top100MCQ.com)

Question 28

Question 28: Why is it slightly easier to push a box once it’s already moving?

A. Because the weight of the box decreasesB. Because sliding friction is less than static frictionC. Because the box gains momentumD. Because gravity helps

Answer

B. Because sliding friction is less than static friction. Once the initial static friction is overcome, less force is needed to maintain the motion. (Friction MCQ Class 8 by Top100MCQ.com)

Question 29

Question 29: What happens to sliding friction if the surfaces in contact become rougher?

A. It decreasesB. It increasesC. It stays the sameD. It becomes zero

Answer

B. It increases. Rougher surfaces create more resistance to sliding. (Friction MCQ Class 8 by Top100MCQ.com)

Question 30

Question 30: Give an example of sliding friction in action.

A. A ball rolling down a hillB. A car braking to a stopC. A boat floating on waterD. A bird flying in the air

Answer

B. A car braking to a stop. The brake pads create sliding friction against the wheels, slowing the car down. (Friction MCQ Class 8 by Top100MCQ.com)

Question 31

Question 31: Why is friction important for walking?

A. It makes us walk fasterB. It prevents our feet from slippingC. It makes us lighterD. It helps us fly

Answer

B. It prevents our feet from slipping. Friction provides the grip needed for controlled movement. (Friction MCQ Class 8 by Top100MCQ.com)

Question 32

Question 32: How does friction help a car move?

A. It makes the car lighterB. It provides grip between the tires and the roadC. It reduces the car’s speedD. It allows the car to fly

Answer

B. It provides grip between the tires and the road. This grip is essential for acceleration and turning. (Friction MCQ Class 8 by Top100MCQ.com)

Question 33

Question 33: What would happen if there was no friction between a pen and paper?

A. We could write easilyB. The pen would slip and we couldn’t writeC. The pen would become heavierD. The paper would catch fire

Answer

B. The pen would slip and we couldn’t write. Friction is necessary for the pen to leave a mark on the paper. (Friction MCQ Class 8 by Top100MCQ.com)

Question 34

Question 34: How do brakes on a bicycle work?

A. By reducing the weight of the bicycleB. By increasing the speed of the bicycleC. By using friction to slow down the wheelsD. By making the wheels smoother

Answer

C. By using friction to slow down the wheels. The brake pads create friction against the wheels, reducing their speed. (Friction MCQ Class 8 by Top100MCQ.com)

Question 35

Question 35: Why is friction important when lighting a match?

A. It makes the matchstick colderB. It creates the flameC. It provides the grip to strike the matchD. It makes the matchstick heavier

Answer

C. It provides the grip to strike the match. Friction ignites the match head when it is struck against the rough surface. (Friction MCQ Class 8 by Top100MCQ.com)

Question 36

Question 36: What is a major disadvantage of friction?

A. It makes objects heavierB. It produces heat, wasting energyC. It makes surfaces smootherD. It increases the speed of moving objects

Answer

B. It produces heat, wasting energy. This heat generation can lead to wear and tear in machines. (Friction MCQ Class 8 by Top100MCQ.com)

Question 37

Question 37: How does friction affect the efficiency of machines?

A. It makes them more efficientB. It has no effect on their efficiencyC. It makes them less efficient due to energy lossD. It makes them lighter

Answer

C. It makes them less efficient due to energy loss. Overcoming friction requires extra energy, reducing efficiency. (Friction MCQ Class 8 by Top100MCQ.com)

Question 38

Question 38: Why do machines wear out over time?

A. Due to their ageB. Due to the force of gravityC. Due to friction causing wear and tearD. Due to changes in temperature

Answer

C. Due to friction causing wear and tear. Constant rubbing leads to damage and wear. (Friction MCQ Class 8 by Top100MCQ.com)

Question 39

Question 39: How does friction affect the speed of moving objects?

A. It increases their speedB. It has no effect on their speedC. It slows them downD. It makes them lighter

Answer

C. It slows them down. Friction acts against motion, reducing speed. (Friction MCQ Class 8 by Top100MCQ.com)

Question 40

Question 40: Why do we add oil to engines?

A. To increase frictionB. To make the engine heavierC. To reduce friction and wearD. To change the engine’s color

Answer

C. To reduce friction and wear. Oil acts as a lubricant, minimizing friction between moving parts. (Friction MCQ Class 8 by Top100MCQ.com)

Question 41

Question 41: Why do we use treads on tires?

A. To make the car look goodB. To increase friction for better gripC. To reduce the car’s weightD. To make the tires last longer

Answer

B. To increase friction for better grip. The treads provide more contact with the road, improving traction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 42

Question 42: Why do athletes use special shoes with spikes?

A. To make them run fasterB. To increase friction and prevent slippingC. To reduce their weightD. To make them jump higher

Answer

B. To increase friction and prevent slipping. The spikes dig into the ground, providing extra grip. (Friction MCQ Class 8 by Top100MCQ.com)

Question 43

Question 43: Why do gymnasts use chalk on their hands?

A. To make their hands softerB. To increase friction for a better gripC. To reduce sweatingD. To make their hands look white

Answer

B. To increase friction for a better grip. Chalk absorbs moisture and increases the friction between their hands and the equipment. (Friction MCQ Class 8 by Top100MCQ.com)

Question 44

Question 44: Why do we use sandpaper to smooth surfaces?

A. To reduce frictionB. To increase friction and remove materialC. To make the surface shinyD. To change the color of the surface

Answer

B. To increase friction and remove material. The rough texture of sandpaper creates enough friction to wear away the surface. (Friction MCQ Class 8 by Top100MCQ.com)

Question 45

Question 45: What is the purpose of using anti-slip mats in bathrooms?

A. To reduce frictionB. To increase friction and prevent slippingC. To make the bathroom look goodD. To absorb water

Answer

B. To increase friction and prevent slipping. The mats provide a textured surface for better grip. (Friction MCQ Class 8 by Top100MCQ.com)

Question 46

Question 46: Why do we add oil to a squeaky door hinge?

A. To increase frictionB. To make the hinge strongerC. To reduce friction and noiseD. To clean the hinge

Answer

C. To reduce friction and noise. The oil lubricates the hinge, allowing it to move more smoothly and quietly. (Friction MCQ Class 8 by Top100MCQ.com)

Question 47

Question 47: How does applying grease to the chain of a bicycle help?

A. It increases frictionB. It makes the chain rustC. It reduces friction and makes pedaling easierD. It makes the chain heavier

Answer

C. It reduces friction and makes pedaling easier. Grease acts as a lubricant, reducing friction between the moving parts of the chain. (Friction MCQ Class 8 by Top100MCQ.com)

Question 48

Question 48: Why do mechanics use lubricants in car engines?

A. To increase friction between engine partsB. To reduce friction and wear, improving efficiencyC. To make the engine run louderD. To cool down the engine

Answer

B. To reduce friction and wear, improving efficiency. Lubricants like oil reduce friction between moving parts, leading to less wear and tear and better fuel economy. (Friction MCQ Class 8 by Top100MCQ.com)

Question 49

Question 49: What is the purpose of using ball bearings in machines?

A. To increase frictionB. To convert sliding friction into rolling friction, reducing friction overallC. To make the machine heavierD. To make the machine look more complex

Answer

B. To convert sliding friction into rolling friction, reducing friction overall. Ball bearings allow parts to roll over each other, which has less friction than sliding. (Friction MCQ Class 8 by Top100MCQ.com)

Question 50

Question 50: Why is it easier to move a heavy box on a wheeled cart than to slide it across the floor?

A. The cart reduces the weight of the boxB. The wheels reduce frictionC. The cart makes the box smootherD. The cart changes the direction of gravity

Answer

B. The wheels reduce friction. Rolling friction is less than sliding friction, making it easier to move the box. (Friction MCQ Class 8 by Top100MCQ.com)

Question 51

Question 51: What are lubricants?

A. Substances that increase frictionB. Substances that make surfaces roughC. Substances that reduce friction between surfacesD. Substances that make objects heavier

Answer

C. Substances that reduce friction between surfaces. Lubricants create a smooth layer between surfaces, reducing contact and friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 52

Question 52: Which of the following is NOT an example of a lubricant?

A. OilB. GreaseC. GraphiteD. Sandpaper

Answer

D. Sandpaper. Sandpaper is abrasive and increases friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 53

Question 53: How do lubricants reduce friction?

A. By making surfaces rougherB. By increasing the contact between surfacesC. By creating a thin layer between surfaces, preventing direct contactD. By making objects heavier

Answer

C. By creating a thin layer between surfaces, preventing direct contact. This separation reduces the interlocking of surface irregularities. (Friction MCQ Class 8 by Top100MCQ.com)

Question 54

Question 54: Why is it important to use the correct type of lubricant for a specific machine?

A. All lubricants are the sameB. Different machines have different requirements for friction and lubricationC. The type of lubricant does not matterD. Using the wrong lubricant will make the machine faster

Answer

B. Different machines have different requirements for friction and lubrication. Factors like temperature, pressure, and the types of materials involved influence the choice of lubricant. (Friction MCQ Class 8 by Top100MCQ.com)

Question 55

Question 55: What could happen if you use too much lubricant in a machine?

A. It will make the machine more efficientB. It will cause the machine to overheatC. It will attract dust and dirt, potentially causing damageD. It will make the machine rust

Answer

C. It will attract dust and dirt, potentially causing damage. Excess lubricant can become a problem by trapping contaminants. (Friction MCQ Class 8 by Top100MCQ.com)

Question 56

Question 56: Why do some machines use air as a lubricant?

A. Air is heavy and provides extra supportB. Air creates a cushion between surfaces, reducing friction without the need for oil or greaseC. Air makes the machine run fasterD. Air cools down the machine

Answer

B. Air creates a cushion between surfaces, reducing friction without the need for oil or grease. This is useful in situations where traditional lubricants are not suitable. (Friction MCQ Class 8 by Top100MCQ.com)

Question 57

Question 57: What is the main purpose of lubricating a bicycle chain?

A. To make the chain shinyB. To prevent the chain from rustingC. To reduce friction and make pedaling easierD. To increase the weight of the chain

Answer

C. To reduce friction and make pedaling easier. A well-lubricated chain reduces the effort required for cycling. (Friction MCQ Class 8 by Top100MCQ.com)

Question 58

Question 58: Why are lubricants important in reducing wear and tear in machines?

A. They make the machine parts softerB. They reduce the contact between surfaces, preventing damage from frictionC. They make the machine run colderD. They prevent the machine from getting old

Answer

B. They reduce the contact between surfaces, preventing damage from friction. Less friction means less wear and tear, extending the life of the machine. (Friction MCQ Class 8 by Top100MCQ.com)

Question 59

Question 59: Can lubricants completely eliminate friction?

A. Yes, with enough lubricant, friction becomes zeroB. No, lubricants can only reduce friction, not eliminate it completelyC. Yes, but only in machines that use air as a lubricantD. No, friction can only be eliminated by making surfaces perfectly smooth

Answer

B. No, lubricants can only reduce friction, not eliminate it completely. Some friction will always exist between surfaces, even with lubrication. (Friction MCQ Class 8 by Top100MCQ.com)

Question 60

Question 60: Why is it important to regularly lubricate moving parts in machines?

A. To change the color of the machine partsB. To keep the machine cleanC. To maintain low friction and prevent wear and tearD. To make the machine heavier

Answer

C. To maintain low friction and prevent wear and tear. Regular lubrication ensures smooth operation and prolongs the life of the machine. (Friction MCQ Class 8 by Top100MCQ.com)

Question 61

Question 61: What type of friction occurs when a ball rolls on the ground?

A. Static frictionB. Sliding frictionC. Rolling frictionD. Fluid friction

Answer

C. Rolling friction. Rolling friction is the resistance encountered when an object rolls over a surface. (Friction MCQ Class 8 by Top100MCQ.com)

Question 62

Question 62: Why is rolling friction generally less than sliding friction?

A. Because rolling objects are lighterB. Because rolling involves less surface area in contactC. Because rolling objects move fasterD. Because rolling objects have smoother surfaces

Answer

B. Because rolling involves less surface area in contact. This reduced contact area leads to less interlocking and friction. (Friction MCQ Class 8 by Top100MCQ.com)

Question 63

Question 63: What is the advantage of using wheels on a suitcase?

A. It makes the suitcase lighterB. It reduces friction, making it easier to pullC. It makes the suitcase more stylishD. It prevents the suitcase from getting scratched

Answer

B. It reduces friction, making it easier to pull. The wheels convert sliding friction to rolling friction, which is easier to overcome. (Friction MCQ Class 8 by Top100MCQ.com)

Question 64

Question 64: Why do we use rollers to move heavy objects?

A. To increase frictionB. To reduce friction and make it easier to move the objectC. To lift the object off the groundD. To prevent the object from tipping over

Answer

B. To reduce friction and make it easier to move the object. Rollers reduce the contact area and friction between the object and the ground. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. It would be much harder to move due to increased friction. Sliding friction is greater than rolling friction. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. Rolling friction. Rolling friction is generally much less than sliding friction. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. Wheels reduce friction, improving efficiency and speed. By reducing friction, cars can move faster and use less fuel. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. To reduce friction and improve efficiency. Reducing friction leads to less wear and tear, lower energy consumption, and better performance. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Bicycle wheels reduce friction, making movement easier. The rolling friction of the wheels is much less than the sliding friction of your feet on the ground. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Machines would require more energy to operate and wear out faster. Increased friction leads to higher energy consumption and increased wear and tear. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Small, smooth balls used to reduce friction in machines. Ball bearings convert sliding friction to rolling friction, reducing friction overall. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. By separating surfaces with small, rolling balls. The balls allow parts to roll over each other instead of sliding, reducing friction. (Friction MCQ Class 8 by Top100MCQ.com)

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B. In bicycles, ceiling fans, and other machines with rotating parts. Ball bearings help these parts rotate smoothly and with less friction. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. They reduce friction, leading to less wear and tear and improved efficiency. By reducing friction, ball bearings help machines last longer and use less energy. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. The machine will become less efficient and may overheat due to increased friction. Damaged ball bearings can increase friction, leading to problems like overheating and reduced performance. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. Friction that occurs when an object moves through a fluid. Fluid friction is the resistance experienced by objects moving in liquids or gases. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Any substance that flows, including liquids and gases. Fluids take the shape of their container and can exert friction on objects moving through them. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Because fluids exert a force against the motion of the object. This opposing force is the fluid friction or drag. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Drag. Drag is the common term for the frictional force experienced by objects moving through fluids. (Friction MCQ Class 8 by Top100MCQ.com)

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B. To reduce drag and improve efficiency. The streamlined shape minimizes the resistance from the air, allowing the plane to fly more efficiently. (Friction MCQ Class 8 by Top100MCQ.com)

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C. It slows them down. The water creates resistance (drag) against the swimmer’s body, reducing their speed. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. To reduce drag and make flying easier. The streamlined shape helps birds minimize air resistance during flight. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

D. The speed, shape, and the nature of the fluid. All these factors influence the amount of drag. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Higher speed creates more drag. As the object moves faster, it encounters more resistance from the fluid. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. It increases drag, opposing the force of gravity. The parachute’s large surface area increases air resistance, slowing the descent. (Friction MCQ Class 8 by Top100MCQ.com)

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B. A more streamlined hull reduces drag and increases speed. By minimizing water resistance, the boat can move faster through the water. (Friction MCQ Class 8 by Top100MCQ.com)

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B. To reduce drag and improve fuel efficiency. The smooth shape minimizes air resistance, allowing the car to use less fuel. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. It reduces drag, allowing them to fly faster and use less fuel. The streamlined shape minimizes air resistance, improving efficiency and speed. (Friction MCQ Class 8 by Top100MCQ.com)

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B. To reduce drag and swim more efficiently. The streamlined shape minimizes water resistance, allowing fish to swim faster and use less energy. (Friction MCQ Class 8 by Top100MCQ.com)

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B. They would experience more drag, reducing speed and fuel efficiency. The increased air resistance would make the car less efficient and slower. (Friction MCQ Class 8 by Top100MCQ.com)

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B. Friction. This is the fundamental definition of friction. (Friction MCQ Class 8 by Top100MCQ.com)

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B. Lubricants. Lubricants like oil and grease reduce friction. (Friction MCQ Class 8 by Top100MCQ.com)

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C. Fluid friction. This is the resistance experienced by objects moving in liquids or gases. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Drag. Drag is another term for fluid friction. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

C. Interlocking. This interlocking contributes to friction. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

A. Ball bearing. Ball bearings reduce friction by converting sliding to rolling. (Friction MCQ Class 8 by Top100MCQ.com)

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C. Rolling friction. This type of friction is generally less than sliding friction. (Friction MCQ Class 8 by Top100MCQ.com)

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C. Sliding friction. This occurs when two surfaces are in motion relative to each other. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

A. Static friction. This is the initial friction that needs to be overcome to start an object moving. (Friction MCQ Class 8 by Top100MCQ.com)

Accepted Answer

B. Magnetic friction. This is not a real type of friction. (Friction MCQ Class 8 by Top100MCQ.com)

Table of Contents

Force of Friction

Definition of friction

Force of friction

Opposing nature of friction

Relative motion

How to measure friction

Spring balance

Factors Affecting Friction

Effect of surface nature on friction

Effect of the smoothness of the surfaces

Surface irregularities

Effect of the force of friction

Effect of the nature of the two surfaces

Static friction

Sliding friction

Friction: A Necessary Evil

Advantages of friction

Disadvantages of friction

Increasing and Reducing Friction

Methods to increase friction

Methods to reduce friction

Lubricants

Wheels Reduce Friction

Rolling friction