Introduction

AP® Physics

1. Basics

2. Kinematics

3. Forces & Newton's Laws

4. Torque & Rotational Dynamics

5. Centripetal Force & Orbits

6. Energy, Work & Power

7. Momentum & Collisions

8. Simple Harmonic Motion & Waves

Now that we understand some of the different
**types of energy**,
let's learn about what makes energy so special: the conservation of energy.

The total sum of the energy in the universe today is the same amount as it was yesterday, and last week, and billions of years ago. The total amount of energy never changes over time, but the amounts of each type of energy can change as energy is converted between different forms. The lecture in the link below from physicist Richard Feynman gives a great summary of how we can think about the conservation of energy:

After we understand **isolated systems** and the conservation of energy, we can learn how energy is transferred into or out of a
**non-isolated system** through work.

**Work** is another word that people use a lot but has a very specific meaning in physics: the transfer of energy into or out of a system
due to a force which causes a displacement. We can calculate work as the force applied to an object multiplied by the displacement of the object.
If you push someone on a sled and increase their speed, you've done work on that person and increased their kinetic energy.
If you lift up a box, you've done work on the box and increased its gravitational potential energy.

One more common word that has a specific physics definition is **power**: a change in energy (or work) per unit of time.
If you increased the speed of the sled or the height of the box in less time then you would have exerted more power.
You might be more familiar with electrical power, but we're only going to cover mechanical power in this course.

4

1. Conservation of Energy

2. Work

- Khan Academy - Work and the work-energy principle
- Khan Academy - Work as the transfer of energy
- Khan Academy - Conservative forces
- Khan Academy - Work is area under the force vs displacement curve

3. Power

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**Answers**

2

- Conservation of Energy

- Professor Dave - Conservation of Energy
- Richard Feynman - Conservation of Energy (22:49)
- Matt Anderson - Escape velocity

- Work

- Professor Dave - Work and Energy
- Khan Academy - Work and the work-energy principle
- Khan Academy - Work and energy diagrams
- Khan Academy - Work as the transfer of energy
- Khan Academy - Conservative forces
- Khan Academy - Work is area under the force vs displacement curve

- Power

- Michel van Biezen - Basic example
- Michel van Biezen - Energy stored in a spring
- Michel van Biezen - Hollow ball rolling down an incline
- Michel van Biezen - Weights on a table
- Matt Anderson - Skier on Inclined Plane
- Matt Anderson - Pendulum using conservation of energy
- Matt Anderson - Spring Launcher
- Khan Academy - Thermal energy from friction

Now that we understand some of the different
**types of energy**,
let's learn about what makes energy so special: the conservation of energy.

The total sum of the energy in the universe today is the same amount as it was yesterday, and last week, and billions of years ago. The total amount of energy never changes over time, but the amounts of each type of energy can change as energy is converted between different forms. The lecture in the link below from physicist Richard Feynman gives a great summary of how we can think about the conservation of energy:

After we understand **isolated systems** and the conservation of energy, we can learn how energy is transferred into or out of a
**non-isolated system** through work.

**Work** is another word that people use a lot but has a very specific meaning in physics: the transfer of energy into or out of a system
due to a force which causes a displacement. We can calculate work as the force applied to an object multiplied by the displacement of the object.
If you push someone on a sled and increase their speed, you've done work on that person and increased their kinetic energy.
If you lift up a box, you've done work on the box and increased its gravitational potential energy.

One more common word that has a specific physics definition is **power**: a change in energy (or work) per unit of time.
If you increased the speed of the sled or the height of the box in less time then you would have exerted more power.
You might be more familiar with electrical power, but we're only going to cover mechanical power in this course.

1. Conservation of Energy

2. Work

- Khan Academy - Work and the work-energy principle
- Khan Academy - Work as the transfer of energy
- Khan Academy - Conservative forces
- Khan Academy - Work is area under the force vs displacement curve

3. Power

Explore this topic

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