# People's Physics Concepts

**At Grade**Created by: CK-12

- 1.
## Units and Problem Solving

Units identify what a specific number refers to. Keeping track of units can help you avoid mistakes when you work out problems.

- 2.
## One-Dimensional Motion

One dimensional motion describes objects moving in straight lines. Speed is a scalar measure of how quickly an object is moving. Velocity is speed with a direction, making it a vector. If an object’s velocity changes, the object is accelerating.

- 3.
## Two-Dimensional and Projectile Motion

This chapter discusses parabolic and projectile motion, acceleration, and velocity.

- 4.
## Newton's Laws

In this chapter, we explore forces and Newton's laws.

- 5.
## Centripetal Forces

Forces which cause objects to turn around continuously in a circle are known as centripetal forces. Centripetal forces cause object's to accelerate by changing their direction.

- 6.
## Gravity

Isaac Newton in a triumph of brilliance declared that there is one law of physics that governs motion and he unified “earthly” bodies and “heavenly” bodies with the The Universal Law of Gravitation.

- 7.
## Momentum Conservation

The total amount of motion in the universe is constant. "Motion" is defined as the product of mass and velocity. This product, called momentum, can be transferred from one object to another in a collision.

- 8.
## Energy Conservation

When any two bodies in the universe interact, they can exchange energy, momentum, or both. The law of conservation of energy states that in any closed system (including the universe) the total quantity of energy remains fixed.

- 9.
## Rotational Motion

The third conservation law is conservation of angular momentum. This vector quantity is the product of rotational velocity and rotational inertia.

- 10.
## Simple Harmonic Motion

The development of devices to measure time, like the pendulum, led to the analysis of periodic motion. Such motion repeats itself in equal intervals of time (called periods) and is also referred to as harmonic motion.

- 11.
## Wave Motion and Sound

Objects in harmonic motion have the ability to transfer some of their energy over large distances. They do so by creating waves in a medium.

- 12.
## Electricity

The lessons in this chapter cover electrostatics at a conceptual level as well as a detailed mathematical approach using Coulomb's Law. Electric fields are covered. Problem solving techniques are also covered.

- 13.
## Electric Circuits: Batteries and Resistors

In these lessons students will gain a strong conceptual footing of electricity. In addition, they will learn how to solve circuit problems containing resistors wired in all different ways.

- 14.
## Magnetism

These lessons cover magnetic fields, magnetic forces and electromagnetic induction.

- 15.
## Electric Circuits: Capacitors

In these lessons the classic parallel plate capacitor is studied as well as all types of capacitor circuits. The RC time constant is also covered.

- 16.
## Light

Light is studied through the concepts of light waves, electromagnetic radiation and fields, electrons, photons, Fermat’s Principle, refraction, diffraction, scattering and color absorption, and dispersion.

- 17.
## Fluids

In these lessons students will learn how the pressure of a fluid is related to depth, how hydraulic press' work and Archemides principle relating buoyancy force to the amount of displaced fluid.

- 18.
## Thermodynamics and Heat Engines

In these lessons we study temperature, the kinetic gas theory, gas pressure, heat engines and pressure-volume graphs.

- 19.
## Special and General Relativity

In these lessons students will learn why time is not a constant in relativity theory and how this gives bizarre phenomenon like the famous 'twin paradox'. Students will learn to calculate 'gamma factors', time dilation and length contraction.

- 20.
## Radioactivity and Nuclear Physics

In these lessons students will develop a deep understanding of radiation and how to solve problems involving the half life and decay constant equations. In addition, the lesson on carbon dating covers an understanding and also develops the skills to solve carbon dating problems.