What You Need to Know

Key Concept Diagram

Kinetic energy: energy of motion; KE = (1/2) x mass x velocity squared

Potential energy: stored energy due to position (gravitational) or condition (elastic, chemical)

Thermal energy: energy due to the movement of particles (heat)

Electrical, light, sound, nuclear, and chemical energy are all forms of energy

Law of Conservation of Energy: energy cannot be created or destroyed, only transformed

Key Vocabulary

Kinetic Energy

Energy an object possesses due to its motion; depends on mass and speed

Potential Energy

Stored energy an object has due to its position or condition (gravitational, elastic, chemical)

Energy Transformation

The process of changing energy from one form to another (e.g. chemical to thermal in a fire)

Conservation of Energy

The principle that the total energy in a closed system remains constant; energy cannot be created or destroyed

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

A ball rolls down a hill. As it rolls, what energy transformation occurs?

Kinetic energy is converted to potential energy Chemical energy is converted to potential energy Thermal energy is converted to kinetic energy Gravitational potential energy is converted to kinetic energy

Question 2

Which energy transformation occurs in a torch (flashlight)?

Chemical energy to electrical energy to light energy Light energy to chemical energy Thermal energy to electrical energy Kinetic energy to electrical energy

Question 3

What does the Law of Conservation of Energy state?

Energy is constantly being created in the universe The total energy in a closed system remains constant; it transforms but is not created or destroyed Energy can be destroyed but not created Faster objects always have more energy

Forms of Energy