Forces and Newton's laws of motion

This is the meat of much of classical physics. We think about what a force is and how Newton changed the world's (and possibly your) view of how reality works.

Newton's laws of motion

This tutorial will expose you to the foundation of classical mechanics--Newton's laws. On one level they are intuitive, on another lever they are completely counter-intuitive. Challenge your take on reality and watch this tutorial. The world will look very different after you're done.
5:26
Newton's first law of motion
Basic primer on Newton's First Law of Motion
7:14
Newton's first law of motion concepts
A little quiz on some of the ideas in Newton's first law
9:32
More on Newton's first law of motion
Newton's First Law (Galileo's Law of Inertia).
Article
What is Newton's first law?
Also called the law of inertia, this is the most important thing to realize about motion.
Exercise
Newton's first law
Testing your conceptual knowledge of Newton's First Law of Motion
7:14
Newton's second law of motion
Newton's Second Law of Motion: F=ma
16:03
More on Newton's second law
In this video David explains how to use Newton's second law when dealing with multiple forces, forces in two dimensions, and diagonal forces.
Article
What is Newton's second law?
Learn about the fact that forces cause acceleration.
8:00
Newton's third law of motion
Every action has an equal and opposite reaction
13:06
More on Newton's third law
In this video David explains some of the common misconceptions in dealing with Newton's Third Law. He also shows how to correctly and reliably identify Third Law force pairs.
Article
What is Newton's third law?
Learn about the fact that forces come in pairs.
Exercise
Newton's third law of motion
Conceptual question testing understanding of Newton's Third Law of Motion
Exercise
All of Newton's laws of motion

Balanced and unbalanced forces

You will often hear physics professors be careful to say "net force" or "unbalanced force" rather than just "force". Why? This tutorial explains why and might give you more intuition about Newton's laws in the process.
8:11
Balanced and unbalanced forces
Primer on identifying balanced and unbalanced forces
6:37
Unbalanced forces and motion
Thinking about what is true about how unbalanced forces relate to motion and acceleration

Slow sock on Lubricon VI

This short tutorial will have you dealing with orbiting frozen socks in order to understand whether you understand Newton's Laws. We also quiz you a bit during the videos just to make sure that you aren't daydreaming about what you would do with a frozen sock.
4:47
Slow sock on Lubricon VI
What would happen to a slowly moving frozen sock on a frictionless planet
7:12
Normal forces on Lubricon VI
Whether the normal force balances the force of gravity for a frozen sock or banana

Inclined planes and friction

We've all slid down slides/snow-or-mud-covered-hills/railings at some point in our life (if not, you haven't really lived) and noticed that the smoother the surface the more we would accelerate (try to slide down a non-snow-or-mud-covered hill). This tutorial looks into this in some depth. We'll look at masses on inclined planes and think about static and kinetic friction.
12:42
Inclined plane force components
Figuring out the components of the force due to gravity that are parallel and perpendicular to the surface of an inclined plane
10:37
Ice accelerating down an incline
Figuring out the acceleration of ice down a plane made of ice
8:41
Force of friction keeping the block stationary
Block of wood kept stationary by the force of friction (Correction made in next video)
0:51
Correction to force of friction keeping the block stationary
Correction to Force of Friction Keeping the Block Stationary
9:09
Force of friction keeping velocity constant
Calculating the coefficient of kinetic friction (correction made in next video)
7:21
Intuition on static and kinetic friction comparisons
Why static friction is harder to overcome than kinetic friction
9:50
Static and kinetic friction example
Thinking about the coefficients of static and kinetic friction
Article
What is friction?
Until now in physics, you've probably been ignoring friction to make things simpler. Now, it's time to include this very real force and see what happens.
Article
What are inclines?
Surfaces usually aren't perfectly horizontal. Learn how to deal with slopes!