Friction

Due to gravity

Due to magnetic force

Due to friction between pencil lead and paper

Due to electrostatic force

Increases

Decreases

Remains same

Becomes permanent

Supports

Opposes

Accelerates

Does not affect

Decrease friction

Increase friction

Make them look stylish

Increase their weight

Spilling oil on the road.

Adding more passengers to the car.

Using tires that have been worn down until they are smooth.

Covering the road with a thin layer of ice.

Water is denser than sand.

The nature of the contact between the boat and water (fluid friction) involves fewer interlocking irregularities than solid sand.

The boat weighs less when it is in water.

Dry sand has no irregularities.

Nature of surface

Force pressing the surfaces

Area of contact

Direction of motion

It will definitely be lower because the smoothness of the glass surface is the most dominant factor in reducing friction.

It will definitely be higher because the frictional force is directly proportional to the total mass of the object.

It will remain exactly the same because the reduction in surface roughness is mathematically canceled by the added mass.

The result cannot be determined with certainty because the two changes have opposing effects on the magnitude of friction.

Static friction

Sliding friction

Limiting friction

Momentum

It decreases because sand acts as a lubricant.

It increases because sand increases the roughness of the surface.

It stays the same because ice is too cold.

It becomes zero.

Static friction < Sliding friction

Static friction > Sliding friction

Rolling friction > Static friction

Sliding friction < Rolling friction

Static friction

Rolling friction

Sliding friction

Air friction

Static friction is acting

Sliding friction is the main force

Rolling friction is acting

There is no friction at all

Very large

Equal to your push

Zero

Greater than your push

Sliding a 10 kg block

Starting the motion of a 10 kg block

Rolling a 10 kg sphere

All require the same force

Increase the weight of the book

Make the table surface rougher

Spread some talcum powder on the table

Push the book on a carpet

The area of contact only

The nature of surfaces and the force pressing them together

The speed of the object only

The shape of the object only

Rolling friction

Static friction

Fluid friction

Zero friction

Due to gravity pulling the string down.

Due to the magnetic properties of the string.

Due to the static friction between the overlapping parts of the string.

Due to the rolling friction within the fibers.

It is destroyed.

It is converted into chemical energy.

It is converted into heat energy in the ball and the ground.

It is converted into potential energy.

Sandpaper has very low friction

Friction between sandpaper and wood wears away the rough spots

Sandpaper adds a layer of plastic to wood

Sandpaper makes the wood cold

It makes the handle hot

It wears out the screw head

It provides the grip to turn the screw

It makes the screwdriver heavy

Carpet is lighter than tiles

Carpet offers more friction

Tiles are magnetic

The trunk becomes heavier on the carpet

Heat production

Wear and tear

Ability to walk

Magnetic attraction

It allows the bow to glide over the strings without any resistance.

It reduces the wear and tear on the bow hair and the strings.

It enables the bow to grip the string and set it into vibration to create sound.

It produces heat energy which is required to change the pitch of the music.

Glass is a transparent material

The smooth glass surface does not provide enough friction to generate the required heat

Glass is too cold to light a match

The matchstick breaks easily on glass

Because they were built that way to look antique

Because of the constant friction from the feet of thousands of visitors over years

Because the stone naturally melts over time

Because of the effect of sunlight on the stone

The engines are being turned off.

The extreme friction between the stationary tires and the fast-moving runway surface burns a small amount of rubber.

The runway is specially treated with smoke-producing chemicals.

The air inside the tires is being released.

It prevents the nut from loosening due to vibrations, maintaining structural integrity.

It makes the bolt heavier, which helps the foundation.

It allows the bolt to be turned without using a wrench.

It generates heat that welds the bolt and nut together permanently.

It provides the lift necessary for the bird to stay in the air.

It acts as a resistance that forces the bird to expend more metabolic energy to fly.

It keeps the bird's feathers clean.

It allows the bird to change direction quickly.

Sliding friction

Static friction

Rolling friction

Fluid friction

Transparent

Too smooth to provide enough friction for the lead to stick

Too hard for the pencil

A bad conductor of heat

Rough concrete

Polished plastic or metal

Rubber

Sandpaper

Make their skin soft

Reduce friction with the bars

Increase friction for a better grip

Keep their hands dry from sweat

Rolling > Sliding > Static

Static > Sliding > Rolling

Sliding > Static > Rolling

Static > Rolling > Sliding

Increasing friction to improve performance

Using a lubricant to reduce friction

Reducing the weight of the cycle

Changing rolling friction into sliding friction

We would be able to walk more quickly

Cars would be able to stop instantly without brakes

We would not be able to write or even hold a pen

Objects would stay at rest and never move

To prevent the wheels from locking up, as static friction (gripping) is stronger than sliding friction (skidding).

To allow the brake pads to cool down by letting air circulate every few seconds.

To increase the temperature of the tires so they can melt the ice on the road.

To create a rhythmic vibration that shakes the water off the brake discs.

Using suction cups or specialized micro-structured adhesives that mimic a gecko's feet.

Polishing the robot's feet to be as smooth as the glass itself.

Adding wheels to the feet so the robot can roll up the glass.

Coating the glass with a thin layer of graphite powder before the robot climbs.

Rubies are extremely hard and can be polished to be very smooth, minimizing friction and wear over decades.

The color of the ruby makes it easier for the watchmaker to see the moving parts.

Rubies have a natural magnetic field that helps the gears rotate faster.

Rubies expand when heated, which helps the watch keep better time in the summer.

Making the surface rough

Increasing the surface area

Streamlining the shape

Painting it a bright color

Its thickness or nature

Its smell

Its chemical formula

Its transparency

Fuel efficiency increases

Fuel efficiency stays the same

Fuel efficiency decreases

The car consumes no fuel

To be closer to the sun

To reduce air resistance/drag

Because there is no gravity there

To increase the noise they make

A square block

A streamlined shape

A flat disc

A hollow cylinder

A racing car trying to reach top speed

An airplane cruising at high altitude

A person descending with a parachute

A cyclist during a sprint

The engine is less efficient at high speeds

The car becomes heavier at high speeds

Air resistance increases dramatically at higher speeds

The tires lose more grip at high speeds

To make sure it can be seen more easily.

To push the fluid away quickly and prevent it from closing back in.

To split the fluid at the front and allow it to close back slowly at the tail to minimize suction/wake drag.

To provide better balance for the heavy engines.

Glycerin

Castor Oil

Water

Air

Drag increases because the frontal area increases.

Drag decreases because a wider boat is more stable.

Drag remains constant because the length is the same.

Drag decreases because the boat doesn't sink as deep.