Friction MCQ Class 8

Correct Answer: B. A force that opposes motion between two surfaces in contact. This is the basic definition of friction.

Correct 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.

Correct Answer: C. Friction. Friction is the force that resists the sliding motion of the book.

Correct Answer: A. Friction. The carpet’s surface creates friction against the car’s wheels, slowing it down.

Correct Answer: B. In the opposite direction. Friction always acts to oppose the motion of an object.

Correct Answer: B. Relative motion. Friction arises when surfaces slide or try to slide against each other.

Correct 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.

Correct Answer: C. It increases. A heavier object presses down with more force, leading to increased friction.

Correct Answer: C. Spring balance. A spring balance measures the force required to move an object against friction.

Correct Answer: A. The extension of a spring is proportional to the force applied. This principle allows the spring balance to accurately measure the force.

Correct Answer: B. A rough road. Rough surfaces have more irregularities that create friction.

Correct Answer: B. The tabletop has less friction than the carpet. Polished surfaces offer less resistance to motion.

Correct Answer: C. Spreading sand on a slippery road. The sand increases the roughness and thus the friction.

Correct Answer: B. Smoother surfaces have less friction. Fewer irregularities mean less interlocking and less friction.

Correct Answer: C. It is reduced significantly. While complete elimination is impossible, smoothing greatly reduces friction.

Correct Answer: C. The interlocking of surface irregularities. Even seemingly smooth surfaces have tiny bumps and grooves that catch on each other.

Correct Answer: B. Friction would increase. More irregularities mean more interlocking and greater resistance to motion.

Correct Answer: C. It increases. Pressing harder increases the contact between irregularities, leading to higher friction.

Correct Answer: B. The heavy box has more friction. Its weight presses it harder against the floor, increasing friction.

Correct Answer: B. Yes, rougher surfaces create more friction. Different materials and textures have varying degrees of friction.

Correct Answer: B. Ice is smoother than the road, offering less friction. The reduced friction makes it difficult to get a grip and walk safely.

Correct Answer: C. Static friction. Static friction is the initial resistance that needs to be overcome to start an object moving.

Correct Answer: C. Static friction. The static friction is strong enough to prevent the box from moving initially.

Correct Answer: C. Static friction. It generally takes more force to overcome static friction and start an object moving than to keep it moving.

Correct Answer: C. It is replaced by sliding friction. Once the object is in motion, sliding friction takes over.

Correct Answer: C. Sliding friction. This friction occurs while the object is in motion, sliding against the surface.

Correct Answer: B. Sliding friction. It’s usually easier to keep an object moving than to start it moving from rest.

Correct 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.

Correct Answer: B. It increases. Rougher surfaces create more resistance to sliding.

Correct Answer: B. A car braking to a stop. The brake pads create sliding friction against the wheels, slowing the car down.

Correct Answer: B. It prevents our feet from slipping. Friction provides the grip needed for controlled movement.

Correct Answer: B. It provides grip between the tires and the road. This grip is essential for acceleration and turning.

Correct Answer: B. The pen would slip and we couldn’t write. Friction is necessary for the pen to leave a mark on the paper.

Correct Answer: C. By using friction to slow down the wheels. The brake pads create friction against the wheels, reducing their speed.

Correct Answer: C. It provides the grip to strike the match. Friction ignites the match head when it is struck against the rough surface.

Correct Answer: B. It produces heat, wasting energy. This heat generation can lead to wear and tear in machines.

Correct Answer: C. It makes them less efficient due to energy loss. Overcoming friction requires extra energy, reducing efficiency.

Correct Answer: C. Due to friction causing wear and tear. Constant rubbing leads to damage and wear.

Correct Answer: C. It slows them down. Friction acts against motion, reducing speed.

Correct Answer: C. To reduce friction and wear. Oil acts as a lubricant, minimizing friction between moving parts.

Correct Answer: B. To increase friction for better grip. The treads provide more contact with the road, improving traction.

Correct Answer: B. To increase friction and prevent slipping. The spikes dig into the ground, providing extra grip.

Correct Answer: B. To increase friction for a better grip. Chalk absorbs moisture and increases the friction between their hands and the equipment.

Correct Answer: B. To increase friction and remove material. The rough texture of sandpaper creates enough friction to wear away the surface.

Correct Answer: B. To increase friction and prevent slipping. The mats provide a textured surface for better grip.

Correct Answer: C. To reduce friction and noise. The oil lubricates the hinge, allowing it to move more smoothly and quietly.

Correct Answer: C. It reduces friction and makes pedaling easier. Grease acts as a lubricant, reducing friction between the moving parts of the chain.

Correct 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.

Correct 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.

Correct Answer: B. The wheels reduce friction. Rolling friction is less than sliding friction, making it easier to move the box.

Correct Answer: C. Substances that reduce friction between surfaces. Lubricants create a smooth layer between surfaces, reducing contact and friction.

Correct Answer: D. Sandpaper. Sandpaper is abrasive and increases friction.

Correct Answer: C. By creating a thin layer between surfaces, preventing direct contact. This separation reduces the interlocking of surface irregularities.

Correct 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.

Correct Answer: C. It will attract dust and dirt, potentially causing damage. Excess lubricant can become a problem by trapping contaminants.

Correct 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.

Correct Answer: C. To reduce friction and make pedaling easier. A well-lubricated chain reduces the effort required for cycling.

Correct 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.

Correct Answer: B. No, lubricants can only reduce friction, not eliminate it completely. Some friction will always exist between surfaces, even with lubrication.

Correct Answer: C. To maintain low friction and prevent wear and tear. Regular lubrication ensures smooth operation and prolongs the life of the machine.

Correct Answer: C. Rolling friction. Rolling friction is the resistance encountered when an object rolls over a surface.

Correct Answer: B. Because rolling involves less surface area in contact. This reduced contact area leads to less interlocking and friction.

Correct Answer: B. It reduces friction, making it easier to pull. The wheels convert sliding friction to rolling friction, which is easier to overcome.

Correct 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.

Correct Answer: C. It would be much harder to move due to increased friction. Sliding friction is greater than rolling friction.

Correct Answer: B. Rolling friction. Rolling friction is generally much less than sliding friction.

Correct Answer: B. Wheels reduce friction, improving efficiency and speed. By reducing friction, cars can move faster and use less fuel.

Correct Answer: C. To reduce friction and improve efficiency. Reducing friction leads to less wear and tear, lower energy consumption, and better performance.

Correct 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.

Correct 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.

Correct Answer: C. Small, smooth balls used to reduce friction in machines. Ball bearings convert sliding friction to rolling friction, reducing friction overall.

Correct Answer: B. By separating surfaces with small, rolling balls. The balls allow parts to roll over each other instead of sliding, reducing friction.

Correct Answer: B. In bicycles, ceiling fans, and other machines with rotating parts. Ball bearings help these parts rotate smoothly and with less friction.

Correct 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.

Correct 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.

Correct 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.

Correct 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.

Correct Answer: C. Because fluids exert a force against the motion of the object. This opposing force is the fluid friction or drag.

Correct Answer: C. Drag. Drag is the common term for the frictional force experienced by objects moving through fluids.

Correct Answer: B. To reduce drag and improve efficiency. The streamlined shape minimizes the resistance from the air, allowing the plane to fly more efficiently.

Correct Answer: C. It slows them down. The water creates resistance (drag) against the swimmer’s body, reducing their speed.

Correct Answer: B. To reduce drag and make flying easier. The streamlined shape helps birds minimize air resistance during flight.

Correct Answer: D. The speed, shape, and the nature of the fluid. All these factors influence the amount of drag.

Correct Answer: C. Higher speed creates more drag. As the object moves faster, it encounters more resistance from the fluid.

Correct Answer: B. It increases drag, opposing the force of gravity. The parachute’s large surface area increases air resistance, slowing the descent.

Correct Answer: B. A more streamlined hull reduces drag and increases speed. By minimizing water resistance, the boat can move faster through the water.

Correct Answer: B. To reduce drag and improve fuel efficiency. The smooth shape minimizes air resistance, allowing the car to use less fuel.

Correct Answer: C. It reduces drag, allowing them to fly faster and use less fuel. The streamlined shape minimizes air resistance, improving efficiency and speed.

Correct Answer: B. To reduce drag and swim more efficiently. The streamlined shape minimizes water resistance, allowing fish to swim faster and use less energy.

Correct Answer: B. They would experience more drag, reducing speed and fuel efficiency. The increased air resistance would make the car less efficient and slower.

Correct Answer: B. Friction. This is the fundamental definition of friction.

Correct Answer: B. Lubricants. Lubricants like oil and grease reduce friction.

Correct Answer: C. Fluid friction. This is the resistance experienced by objects moving in liquids or gases.

Correct Answer: C. Drag. Drag is another term for fluid friction.

Correct Answer: C. Interlocking. This interlocking contributes to friction.

Correct Answer: A. Ball bearing. Ball bearings reduce friction by converting sliding to rolling.

Correct Answer: C. Rolling friction. This type of friction is generally less than sliding friction.

Correct Answer: C. Sliding friction. This occurs when two surfaces are in motion relative to each other.

Correct Answer: A. Static friction. This is the initial friction that needs to be overcome to start an object moving.

Correct Answer: B. Magnetic friction. This is not a real type of friction.