Physical Science Quiz 2

Kinetic Energy

The energy of motion; depends on an object's mass and speed.

Factors that determine kinetic energy

Mass and speed — higher mass or faster speed = more kinetic energy.

Kinetic energy of two bricks

They have the same kinetic energy because both mass and speed are equal.

Kinetic energy of two cars

The heavier car — kinetic energy increases with mass when speed is constant.

Kinetic energy of a resting object

A resting object has no kinetic energy; motion gives it energy regardless of size.

Potential Energy

Stored energy due to position or condition.

Gravitational potential energy greatest

When an object is highest above the ground.

Factors that determine gravitational potential energy

Mass, height, and gravity (GPE = m × g × h).

Gravitational potential energy of bowling ball vs ping-pong ball

No; the bowling ball has more GPE because it has more mass.

Thermal Energy

Energy related to the motion of particles in matter.

Factors determining thermal energy in water

Temperature and mass — more molecules or higher temperature = more energy.

Thermal energy in hot and cold objects

Yes, all matter has thermal energy; hotter matter has more because particles move faster.

Thermal energy and marble on a track

As potential energy decreases (downhill), kinetic energy increases — like heating increases particle motion.

Forms of Potential Energy

Gravitational, Chemical, Nuclear, and Elastic.

Example of gravitational potential energy transforming

A rock falling — GPE turns into kinetic energy.

Roller coaster energy levels

PE is highest at the top of the hill; KE is highest at the bottom.

Law of Conservation of Energy

Energy cannot be created or destroyed, only transformed.

Everyday energy transformations

Toaster: Electrical → Thermal; Light bulb: Electrical → Radiant; Car engine: Chemical → Mechanical.

Heat

Energy transfer from warmer to cooler objects.

Temperature

Average motion (kinetic energy) of particles.

Heat transfer and temperature sensation

Heat transfer — energy moves from warm to cool objects.

Difference between cooler and warmer matter

Cooler matter's molecules move slower; warmer matter's move faster.

Energy transfer when holding a warm cookie

By conduction — direct contact.

Sunlight and thermal energy

It increases through radiation from the sun.

Examples of heat transfer

Conduction: Touching a metal spoon in hot soup; Convection: Warm air rising in a room; Radiation: Feeling heat from the sun.

Swing Example (Energy Transformation)

PE is highest at the top, KE is highest at the bottom.

PE increasing/decreasing in a swing

PE increases as the swing goes up; decreases as it goes down.

Swing motion duration

No; friction and air resistance turn energy into heat.

Conservation of energy in a swing

Total energy stays constant; it just changes forms (PE ↔ KE ↔ Thermal).

Matter

Anything that has mass and takes up space.

Energy

The ability to cause change or do work.

Types of matter made of atoms

All types — solids, liquids, gases, and plasma.

Law of Conservation of Mass

Matter cannot be created or destroyed, only changed in form.

Example of conservation of mass

Burning wood — ash + gases = same total mass as the original wood.

States of Matter

Solid: Vibrate in place, tightly packed; Liquid: Move freely but close together; Gas: Move quickly and spread far apart.

Connection between molecules in states of matter

Strongest in solids, weaker in liquids, weakest in gases.

Space between atoms in states of matter

Smallest in solids, medium in liquids, largest in gases.

Law of Conservation of Matter (Gas or Solid Produced)

If a gas or solid is produced, the law still applies — total mass remains the same; it's just in a different state.