# One-dimensional motion

Contents

In this tutorial we begin to explore ideas of velocity and acceleration. We do exciting things like throw things off cliffs (far safer on paper than in real life) and see how high a ball will fly in the air.

## Displacement, velocity, and time

This tutorial is the backbone of your understanding of kinematics (i.e., the motion of objects). You might already know that distance = rate x time. This tutorial essentially reviews that idea with a vector lens (we introduce you to vectors here as well). So strap your belts (actually this might not be necessary since we don't plan on decelerating in this tutorial) and prepare for a gentle ride of foundational physics knowledge.

9:30

Introduction to physics

An overview video of what physics is about as we delve deeper in future videos!

Article

What is physics?

Before diving into the details, let's think about what physics is in the first place.

8:39

Intro to vectors & scalars

Distance, displacement, speed and velocity. Difference between vectors and scalars.

Article

What is displacement?

Analyzing motion can get complicated. Learning precise vocabulary will help.

11:45

Calculating average velocity or speed

Example of calculating speed and velocity

9:35

Solving for time

Simple example of solving for time given distance and rate

5:00

Displacement from time and velocity example

Worked example of calculating displacement from time and velocity

4:38

Instantaneous speed and velocity

Instantaneous speed and velocity looks at really small displacements over really small periods of time

Article

What is velocity?

Velocity or speed? Instantaneous or average? Keep building your physics vocabulary.

15:20

Position vs. time graphs

David explains how to read a position vs. time graph. He then explains how to use the graph to determine the following quantities: displacement, distance, average velocity, average speed, instantaneous velocity, and instantaneous speed.

Article

What are position vs. time graphs?

See what we can learn from graphs that relate position and time.

## Acceleration

In a world full of unbalanced forces (which you learn more about when you study Newton's laws), you will have acceleration (which is the rate in change of velocity). Whether you're thinking about how fast a Porsche can get to 60mph or how long it takes for a passenger plane to get to the necessary speed for flight, this tutorial will help.

9:06

Acceleration

Calculating the acceleration of a Porsche

Article

What is acceleration?

Velocity describes how position changes; acceleration describes how velocity changes. Two layers of change!

8:08

Airbus A380 take-off time

Figuring how long it takes an a380 to take off given a constant acceleration

5:29

Airbus A380 take-off distance

How long of a runway does an A380 need?

9:26

Why distance is area under velocity-time line

Understanding why distance is area under velocity-time line

Article

What are velocity vs. time graphs?

See what we can learn from graphs that relate velocity and time.

14:38

Acceleration vs. time graphs

David explains how to read an acceleration vs. time graph. He then shows how the area under the curve gives the change in velocity and does a few examples.

Article

What are acceleration vs. time graphs?

See what we can learn from graphs that relate acceleration and time.

## Kinematic formulas and projectile motion

We don't believe in memorizing formulas and neither should you (unless you want to live your life as a shadow of your true potential). This tutorial builds on what we know about displacement, velocity and acceleration to solve problems in kinematics (including projectile motion problems). Along the way, we derive (and re-derive) some of the classic formulas that you might see in your physics book.

14:10

Average velocity for constant acceleration

Calculating average velocity when acceleration is constant

14:16

Acceleration of aircraft carrier take-off

Using what we know about take-off velocity and runway length to determine acceleration

9:58

Deriving displacement as a function of time, acceleration, and initial velocity

Deriving displacement as a function of time, constant acceleration and initial velocity

16:18

Plotting projectile displacement, acceleration, and velocity

Plotting projectile displacement, acceleration, and velocity as a function to change in time

8:51

Projectile height given time

Figuring out how high a ball gets given how long it spends in the air

7:09

Deriving max projectile displacement given time

Deriving a formula for maximum projectile displacement as a function of elapsed time

11:43

Impact velocity from given height

Determining how fast something will be traveling upon impact when it is released from a given height

Article

What are the kinematic formulas?

Here are the main equations you can use to analyze situations with constant acceleration.

7:31

Viewing g as the value of Earth's gravitational field near the surface

Viewing g as the value of Earth's gravitational field near the surface rather than the acceleration due to gravity near Earth's surface for an object in freefall

## Old videos on projectile motion

This tutorial has some of the old videos that Sal first did around 2007. This content is covered elsewhere, but some folks like the raw (and masculine) simplicity of these first lessons (Sal added the bit about "masculine").

9:07

Projectile motion (part 1)

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

9:13

Projectile motion (part 2)

A derivation of a new motion equation

9:04

Projectile motion (part 3)

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

8:57

Projectile motion (part 4)

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

9:33

Projectile motion (part 5)

How fast was the ball that you threw upwards?