# Physics

Khan Academy

Projectile motion, mechanics and electricity and magnetism. Solid understanding of algebra and a basic understanding of trigonometry necessary.

• ##### Introduction to Motion Part 1
Salman Khan

Introduction to basic physics of motion. Introduces the concept of variable velocity/acceleration.

• ##### Introduction to Motion Part 2
Salman Khan

More on how velocity, distance, acceleration and time relate to each other.

• ##### Introduction to Motion Part 3
Salman Khan

Using the basic equations of distance and velocity to solve motion problems.

• ##### Projectile Motion Part 1
Salman Khan

Using the equations of motion to figure out things about falling objects.

• ##### Projectile Motion Part 2
Salman Khan

A derivation of a new motion equation.

• ##### Projectile Motion Part 3
Salman Khan

An example of solving for the final velocity when you know the change in distance, time, initial velocity, and acceleration.

• ##### Projectile Motion Part 4
Salman Khan

Solving for time when you are given the change in distance, acceleration, and initial velocity.

• ##### Projectile Motion Part 5
Salman Khan

How fast was the ball that you threw upwards?

• ##### Projectile Motion Part 6
Salman Khan

More on the ball throwing game.

• ##### Projectile Motion Part 7
Salman Khan

How high did the ball go?

• ##### Projectile Motion Part 8
Salman Khan

A little leftover from part 7.

• ##### Projectile Motion Part 9
Salman Khan

Another example of projectile motion.

• ##### Projectile Motion Part 10
Salman Khan

Some more examples with projectile motion.

• ##### 2-Dimensional Projectile Motion Part 1
Salman Khan

Using vectors to solve 2 dimensional projectile motion problems.

• ##### 2-Dimensional Projectile Motion Part 2
Salman Khan

More on 2 dimensional projectile motion.

• ##### 2-Dimensional Projectile Motion Part 3
Salman Khan

Completing our first example from parts 1 and 2.

• ##### 2-Dimensional Projectile Motion Part 4
Salman Khan

Another example of a 2-dimensional projectile motion problem.

• ##### 2-Dimensional Projectile Motion Part 5
Salman Khan

The second part of the last projectile motion problem.

• ##### Optimal Angle for Projectile Part 1
Salman Khan

Optimal Angle for Projectile Part 1.

• ##### Optimal Angle for Projectile Part 2
Salman Khan

Optimal angle for a projectile part 2 - Hangtime.

• ##### Optimal Angle for Projectile Part 3
Salman Khan

Horizontal distance as a function of angle (and speed).

• ##### Optimal Angle for Projectile Part 4
Salman Khan

Optimal Angle for Projectile Part 4.

• ##### Newton's First Law of Motion
Salman Khan

Introduction to newton's first law of motion. Inertial frames of reference.

• ##### Newton's Second Law of Motion
Salman Khan

An introduction to Newton's Second Law of Motion.

• ##### Newton's Third Law of Motion
Salman Khan

Intuition behind Newton's Third Law of Motion.

• ##### Newton's Law Problem Part 1
Salman Khan

Examples of exercises using Newton's laws.

• ##### Newton's Law Problem Part 2
Salman Khan

A couple of more examples involving Newton's Laws.

• ##### Newton's Laws
Salman Khan

A problem involving a braking train.

• ##### Introduction to Tension
Salman Khan

An introduction to tension. Solving for the tension(s) in a set of wires when a weight is hanging from them.

• ##### Tension Part 2
Salman Khan

A slightly more difficult tension problem.

• ##### Tension in an Accelerating System
Salman Khan

The second part to the complicated problem. We figure out the tension in the wire connecting the two masses. Then we figure our how much we need to accelerate a pie for it to safely reach a man's face.

• ##### Introduction to Momentum
Salman Khan

What momentum is. A simple problem involving momentum.

• ##### Momentum: Ice Skater Throws a Ball
Salman Khan

A simple conservation of momentum problem involving an ice skater and a ball.

• ##### 2-Dimensional Momentum Problem Part 1
Salman Khan

An example of conservation of momentum in two dimensions.

• ##### 2-Dimensional Momentum Problem Part 2
Salman Khan

We finish the 2-dimensional momentum problem.

• ##### Introduction to Work and Energy Part 1
Salman Khan

Introduction to work and energy.

• ##### Introduction to Work and Energy Part 2
Salman Khan

More on work. Introduction to Kinetic and Potential Energies.

• ##### Conservation of Energy
Salman Khan

Using the law of conservation of energy to see how potential energy is converted into kinetic energy.

• ##### Work/Energy Problem with Friction
Salman Khan

A conservation of energy problem where all of the energy is not conserved.

• ##### Mechanical Advantage Part 1
Salman Khan

Introduction to simple machines, mechanical advantage and moments.

• ##### Mechanical Advantage Part 2
Salman Khan

More on mechanical advantage, levers and moments.

• ##### Mechanical Advantage Part 3
Salman Khan

Introduction to pulleys and wedges.

• ##### Center of Mass
Salman Khan

Introduction to the center of mass.

• ##### Introduction to Torque
Salman Khan

An introduction to torque.

• ##### Moments Part 1
Salman Khan

Introduction to moments.

• ##### Moments Part 2
Salman Khan

2 more moment problems.

• ##### Unit Vector Notation Part 1
Salman Khan

Expressing a vector as the scaled sum of unit vectors.

• ##### Unit Vector Notation Part 2
Salman Khan

More on unit vector notation. Showing that adding the x and y components of two vectors is equivalent to adding the vectors visually using the head-to-tail method.

• ##### Projectile Motion with Ordered Set Notation
Salman Khan

Solving the second part to the projectile motion problem (with wind gust) using ordered set vector notation.

• ##### Centripetal Acceleration Part 1
Salman Khan

Intuition behind what it takes to make something travel in a circle.

• ##### Centripetal Acceleration Part 2
Salman Khan

More intuition on centripetal acceleration. A simple orbit problem.

• ##### Centripetal Acceleration Part 3
Salman Khan

How fast does a car need to go to complete a loop-d-loop.

• ##### Visual Proof: a= v^2/r
Salman Khan

Visual proof that centripetal acceleration = v^2/r.

• ##### Calculus Proof that a=v^2/r
Salman Khan

Using calculus and vectors to show that centripetal acceleration = v^2/r.

• ##### Introduction to Angular Velocity
Salman Khan

Angular velocity or how fast something is spinning.

• ##### Conservation of Angular Momentum
Salman Khan

Angular momentum is constant when there is no net torque.

• ##### Introduction to Newton's Law of Gravitation
Salman Khan

A little bit on gravity.

• ##### Gravitation
Salman Khan

A little bit more on gravity.

• ##### Spring and Hooke's Law
Salman Khan

Introduction to Hooke's Law.

• ##### Potential Energy Stored in a Spring
Salman Khan

Work needed to compress a spring is the same thing as the potential energy stored in the compressed spring.

• ##### Spring Potential Energy Example (Mistake in Math)
Salman Khan

A spring, a frozen loop-d-loop and more! (See if you can find the mistake I made and get the right answer!).

• ##### Harmonic Motion Part 1
Salman Khan

Intuition behind the motion of a mass on a spring (some calculus near the end).