UNIT TEST 4

Friction is a force that __________ the movement of an object.

resists

__________ is the friction between two objects that prevents them from sliding across each other.

Traction

A __________ is a substance that reduces friction between surfaces.

Lubricant

__________ is the sticking together of two different materials.

Adhesion

__________ is the force that attracts objects toward each other, e.g., Earth’s gravity pulls objects toward it.

Gravity

__________ refers to the attraction between molecules or materials of the same type, causing them to stick together.

Cohesion

__________ is the frictional force that slows down an object moving through air or water.

Drag

__________ is the study of how an object’s shape affects its movement through air or water, aiming to reduce drag.

Aerodynamics

The __________ states that objects closer together exert a stronger gravitational pull than those farther apart.

Law of Universal Gravitation

__________ is a force acting on a body moving in a circular path, directed toward the center.

Centripetal Force

The __________ is the maximum speed an object reaches when falling through the atmosphere under the influence of gravity.

Terminal Velocity

The reason you slow down when hitting a dry patch on a water slide is that there is __________ when there is no water compared to when water is present.

less friction

The wet bar of soap is slippery because it has __________ compared to a dry one.

less friction

Friction is stronger on rough surfaces than on smooth surfaces because rough surfaces have __________ points of contact.

more

Water decreases friction more than oil because it is __________ than oil, allowing it to flow and reduce friction more effectively.

less viscous

When we talk about adhesion, we usually refer to __________ substances.

sticky

When rubbing your hands together, the __________ you rub, the more friction is created, which leads to heat.

harder

You need special boots for rocky hikes because they provide __________, reducing the risk of slipping.

better grip

Cohesion refers to the __________ between molecules of the same material.

attraction

__________ is the term we use for sticky items.

Adhesives

If your car is stuck in the mud, it is better to put __________ and rocks under it.

sticks

Ballerinas don’t slip while spinning because the crew puts a sticky substance on the stage to increase __________.

traction

The Latin word for fluid is __________.

Fluo

Water slows you down underwater because it exerts __________ against you as you move.

friction

American football players use special gloves made from polymers to increase __________ between the ball and their hands.

traction

It is difficult to keep your hand level when holding it out of a car window because of __________—the resistance created by air.

drag

Jets, submarines, fish, and birds are shaped to reduce __________ and optimize aerodynamics.

drag

Energy is the ability to __________.

do work

__________ energy refers to energy of motion (e.g., running, speaking).

Kinetic

__________ energy is stored energy waiting to be used (e.g., a stretched rubber band).

Potential

The Law of __________ states that energy cannot be created or destroyed, only transferred or transformed.

Conservation of Energy

Chemical energy is stored in __________, fuel, and batteries.

food

__________ energy is energy from moving particles, like fire or boiling water.

Thermal

__________ energy is the energy in moving objects, like a rolling ball.

Mechanical

Electrical energy is energy from moving __________.

electrons

__________ energy travels in waves through air or water.

Sound

__________ energy is stored in atoms and released through nuclear reactions.

Nuclear

Fossil fuels are formed from buried plants and __________ over thousands of years.

animals

Coal is burned to produce __________.

electricity

Natural gas is used for __________ and cooking.

heating

Non-renewable energy sources take __________ of years to form.

millions

Solar energy is power from the __________, used in solar panels.

sun

Wind energy generates electricity using __________.

turbines

Hydropower uses flowing water to turn __________.

turbines

Geothermal energy utilizes heat from __________ the Earth.

inside

____________ is made from plants like corn and sugarcane.

Biofuels

Fossil fuels cause __________ but are currently the most widely used.

pollution