# Causes of Motion Episode 7 of Physics and Our Universe: How It All Works Series

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Describing Motion
Motion is everywhere, at all scales. Learn the difference between distance and displacement, and between speed and velocity. Add to these the concept of acceleration, which is the rate of change of velocity, and you are ready to delve deeper into the fundamentals of motion.
Rotational Motion
Turn your attention to rotational motion. Rotational analogs of acceleration, force, and mass obey a law related to Newton's second law. This leads to the concept of angular momentum and the all-important -conservation of angular momentum, which explains some surprising and seemingly counterintuitive phenomena involving rotating objects.
Back and Forth: Oscillatory Motion
Start a new section in which you apply Newtonian mechanics to more complex motions. In this episode, study oscillations, a universal phenomenon in systems displaced from equilibrium. A special case is simple harmonic motion, exhibited by springs, pendulums, and even molecules.
Using Newton's Laws: 1-D motion
Investigate Newton's second law, which relates force, mass, and acceleration. Focus on gravity, which results in a force, called weight, that's proportional to an object's mass. Then take a ride in an elevator to see how your measured weight changes due to acceleration during ascent and descent.
The Fundamental Science
Take a quick trip from the subatomic to the galactic realm as an introduction to physics, the science that explains physical reality at all scales. Professor Wolfson shows how physics is the fundamental science that underlies all the natural sciences. He also describes phenomena that are still beyond its explanatory…
Languages of Physics
Understanding physics is as much about language as it is about mathematics. Begin by looking at how ordinary terms, such as theory and uncertainty, have a precise meaning in physics. Learn how fundamental units are defined. Then get a taste of the basic algebra that is used throughout the course.
Falling Freely
Use concepts from the previous episode to analyze motion when an object is under constant acceleration due to gravity. In principle, the initial conditions in such cases allow the position of the object to be determined for any time in the future, which is the idea behind Isaac Newton's clockwork…
It's a 3-D World!
Add the concept of vector to your physics toolbox. Vectors allow you to specify the magnitude and direction of a quantity such as velocity. The vector's direction can be along any axis, allowing analysis of motion in three dimensions. Then use vectors to solve several problems in projectile motion.
Going in Circles
Circular motion is accelerated motion, even if the speed is constant, because the direction, and hence the velocity, is changing. Analyze cases of uniform and non-uniform circular motion. Then close with a problem challenging you to pull out of a dive in a jet plane without blacking out or crashing.
Action and Reaction
According to Newton's third law, for every action there is an equal and opposite reaction. Professor Wolfson has a clearer way of expressing this much-misunderstood phrase. Also, see several demonstrations of action and reaction, and learn about frictional forces through examples such as antilock brakes.
Newton's Laws in 2 and 3 Dimensions
Consider Newton's laws in cases of two and three dimensions. For example, how fast does a rollercoaster have to travel at the top of a loop to keep passengers from falling out? Is there a force pushing passengers up as the coaster reaches the top of its arc? The answer…
Work and Energy
See how the precise definition of work leads to the concept of energy. Then explore how some forces give back the work done against them. These conservative forces lead to the concept of stored potential energy, which can be converted to kinetic energy. From here, develop the important idea of…