Feynman Lectures Simplified 1A: Basics of Physics & Newton's Laws

By Robert Piccioni

Feynman Simplified gives mere mortals access to the fabled Feynman Lectures on Physics.

As a Caltech undergraduate, I had the amazing opportunity to learn physics directly from the greatest scientist of our age. He had an uncanny ability to unravel the most complex mysteries, reveal the key underlying principles, and provide a profound understanding of nature. His style and enthusiasm were as important as the facts and equations.

It’s a great shame that so many had so much difficulty with the original course. I hope to help change that and bring Feynman’s genius to a wider audience.

For those who have struggled with the Big Red Books, and for those who were reluctant to take the plunge, Feynman Simplified is for you.

Feynman Simplified makes Feynman’s lectures easier to understand without watering down his brilliant insights.

Feynman Simplified is self-contained; you don’t need to go back and forth between this book and The Feynman Lectures on Physics.

Feynman Simplified: Physics 1A covers about the first quarter of Volume 1, the freshman course, of The Feynman Lectures on Physics.

There is no better way to truly learn physics than from a truly great physicist, Feynman taught us more than just physics — he taught us how to think like a physicist.

• Language: English
• Publisher: Robert Piccioni
• Release date: May 25, 2014
• ISBN: 9781311083807

Robert Piccioni

Dr Robert Piccioni is a physicist, public speaker, educator and expert on cosmology and Einstein's theories. His "Everyone's Guide Series" e-books makes the frontiers of science accessible to all. With short books focused on specific topics, readers can easily mix and match, satisfying their individual interests. Each self-contained book tells its own story. The Series may be read in any order or combination. Robert has a B.S. in Physics from Caltech, a Ph.D. in High Energy Physics from Stanford University, was a faculty member at Harvard University and did research at the Stanford Linear Accelerator in Palo Alto, Calif. He has studied with and done research with numerous Nobel Laureates. At Caltech, one of his professors was Richard Feynman, one of the most famous physicists of the 20th century, and a good family friend. Dr. Piccioni has introduced cutting-edge science to numerous non-scientific audiences, including school children and civic groups. He was guest lecturer on a National Geographic/Lindblad cruise, and has given invited talks at Harvard, Caltech, UCLA, and Stanford University.

Book preview

Feynman Simplified

1A: Basics of Physics

& Newton’s Laws

Everyone’s Guide

to the

Feynman Lectures on Physics

by

Robert L. Piccioni, Ph.D.

Second Edition

Copyright © 2016

by

Robert L. Piccioni

Real Science Publishing

3949 Freshwind Circle

Westlake Village, CA 91361, USA

Edited by Joan Piccioni

All rights reserved, including the right of

reproduction in whole or in part, in any form.

Visit our web site

www.guidetothecosmos.com

Everyone’s Guide

to the

Feynman Lectures on Physics

Feynman Simplified gives mere mortals access to the fabled Feynman Lectures on Physics.

Caltech Professor and Nobel Laureate Richard Feynman was the greatest scientist since Einstein. I had the amazing opportunity to learn physics directly from the world’s best physicist. He had an uncanny ability to unravel the most complex mysteries, reveal underlying principles, and profoundly understand nature. No one ever presented introductory physics with greater insight than did Richard Feynman. He taught us more than physics — he taught us how to think like a physicist.

But, the Feynman Lectures are like sipping from a fire hose. His mantra seemed to be: No Einstein Left Behind. He sought to inspire the more advanced and excited student, and ensure even the most intelligent student was unable to completely encompass everything.

My goal is to reach as many eager students as possible, and bring Feynman’s genius to a wider audience. For those who have struggled with the Big Red Books, and for those who were reluctant to take that plunge, Feynman Simplified is for you. I make Feynman’s lectures easier to understand without watering down his brilliant insights.

Feynman Simplified is self-contained; you do not need to go back and forth between this book and the Lectures. But, for those who wish to read both, I provide references to Feynman’s books thusly: V1p12-9 denotes Volume 1, chapter 12, page 9. So, if you have trouble with Feynman’s description of reversible machines in Volume 1 page 4-2, simply search this eBook for V1p4-2. Rather than track his lectures line-for-line, some material is presented in a different sequence. The best way to divide material into one-hour lectures is not necessarily the best way to present it in a book.

Many major discoveries have been made in the last 50 years, Feynman Simplified updates these lectures informing readers of the latest developments. Links to additional information on many topics are provided in the text.

Physics is one of the greatest adventures of the human mind, but with adventure comes challenge. Even simplified Feynman physics will be one of the most intellectually challenging courses you will ever take. Give it your very best and you will get the most out of it.

Enjoy Exploring.

THIS BOOK

Feynman Simplified: Physics 1A covers about the first quarter of Volume 1, the freshman course, of The Feynman Lectures on Physics. This Second Edition of 1A contains many improvements, thanks in large part to feedback from readers like you.

The topics we explore include:

What is Science? What is Physics?

Nature’s Limitless Diversity & Underlying Unity

Nature’s Smallest & Largest Parts

Matter is Made of Atoms

Atoms are made of Elementary Particles

Measurement, Units & Dimensional Analysis

Time, Distance & Motion

Energy and its many forms:

Kinetic – Energy due to Motion

Work – Force × Distance

Heat – Atomic-scale Motion

Potential – Energy due to Location

Electromagnetic

Mass – Condensed Energy

Momentum — Mass in Motion

Conservation Laws: Total Amounts that Never Change

Energy, the Sum of all its Forms

Momentum, in any direction

Electric Charge

Newton’s Laws of Motion

Universal Gravity: Orbits & Tides

The Character of Force

Essential Math for Physicists:

Zeno’s Paradox & Infinite Series

Vectors – 3-D Simplified

Derivatives — Rate of Change

Integrals — Sum of Small Changes

To learn more about the Feynman Simplified series, to receive updates, and send us your comments, click here. 

To further Simplify your adventure, learn about my Math for Physicists that explains the math to master Feynman physics.

Looking for information about a specific topic? Peruse our free downloadable index to the entire Feynman Simplified series.

If you enjoy this eBook please do me the great favor of rating it on Amazon.com or BN.com.

Table of Contents

Chapter 1: What is Science?

Chapter 2: Basic Physics

Chapter 3: Physics: Mother of All Sciences

Chapter 4: Conservation of Energy

Chapter 5: Time and Distance

Chapter 6: Motion

Chapter 7: Newton’s Laws of Motion

Chapter 8: Newton’s Law of Universal Gravity

Chapter 9: The Character of Force

Chapter 10: Work & Potential Energy

Chapter 11: Review

Chapter 1

What is Science?

Nobel Laureate Richard P. Feynman (1918-1988) begins his legendary Feynman Lectures on Physics by examining the meaning, methodology, capability, and purpose of science.

§1.1 Objectives & Methods of Science

In V1p2-1, Feynman writes:

"The things with which we concern ourselves in science appear in myriad forms, and with a multitude of attributes. For example, if we stand on the shore and look at the sea, we see the water, the waves breaking, the foam, the sloshing motion of the water, the sound, the air, the winds and the clouds, the sun and the blue sky, and light; there is sand and there are rocks of various hardness and permanence, color and texture. There are animals and seaweed, hunger and disease, and the observer on the beach; there may be even happiness and thought. Any other spot in nature has a similar variety of things and influences. It is always as complicated as that, no matter where it is. Curiosity demands that we ask questions, that we try to put things together and try to understand the multitude of aspects as perhaps resulting from the action of a relatively small number of elemental things and forces acting in an infinite variety of combinations.

"For example: Is the sand other than the rocks? That is, is the sand perhaps nothing but a great number of very tiny stones? Is the moon a great rock? If we understood rocks, would we also understand the sand and the moon? Is the wind a sloshing of air analogous to the sloshing motion of water in the sea? What common features do different movements have? What is common to different kinds of sound? How many different colors are there? And so on. In this way we try gradually to analyze all things, to put together things which at first sight look different, with the hope that we may be able to reduce the number of different things and thereby understand them better."

Over several centuries, people devised a systematic method to attempt to answer such questions: the scientific method, comprising observation, reason, imagination, and experiment. Science is society’s organized effort to understand nature. Science does not attempt to answer all questions, even perhaps not all of the most important questions. Rather, science focuses on observable physical reality.

By understanding the physics of our world, we hope to better appreciate its magnificence, and better help society take advantage of opportunities and avoid hazards.

The key principle of science that distinguishes it from other human endeavors is its emphasis on testing. In V1p1-1, Feynman says: "Experiment is the sole judge of scientific ‘truth’." Science has no Pope, no Supreme Court, and no Parliament empowered to enact its laws. Even the most esteemed scientists are not infallible. Einstein was wrong about half the time — the rest of us aren’t nearly that good. Science advances by insisting that truth be determined objectively, by observations of nature.

Prime scientific evidence is not locked in some vault, rather it is reproducible by any competent person, anywhere, anytime.

For example, the generally accepted atomic mass of oxygen is 15.999±0.004 amu because that is the consensus of many independent measurements. But no one should carve that number in stone, because this is only the currently accepted value. One day more precise measurements might yield 15.991±0.001. If confirmed, this new result will become the new generally accepted value.

If all this sounds a bit messy, that’s because it is — scientific knowledge advances but is rarely absolute. Quantifying uncertainty and intelligently dealing with it are essential in science. No one said science was easy.

Science progresses when its two primary disciplines, experiment and theory, work well together. Feynman says experiments give us hints from which we hope human imagination will guess nature’s wonderful, simple, but very strange patterns so we can create mental models of how nature works.

Humans excel at creating mental models of reality; it is one of our most distinguishing attributes. These models are sometimes called theories, hypotheses, or even laws of nature. But model seems less pretentious and that term is becoming more common.

After creating a model, the next critical steps are prediction and testing. Feynman said: The basis of science is its ability to predict [correctly]. (I follow the standard convention when quoting others: any changes I make are enclosed in [ ]’s.)

People create an endless bounty of ideas about how nature works. Many of these ideas are wonderful and innovative, but almost all are incorrect — nature holds its secrets close. Science succeeds by demanding that our models make unique and definitive predictions, all of which must be validated by experiment. As Einstein said: a thousand experiments cannot prove me right, but one experiment can prove me wrong.

§1.2 Brownian Motion

An example should help clarify the process of science.

For 25 centuries, scientists and natural philosophers debated in vain whether matter was continuous or discrete. Here is the difference: if a drop of water is cut in half, and then halved again and again, ad infinitum, will we ever reach an end — a discrete, irreducible, smallest piece of water? Or will we always have a continuous drop that can be halved yet again?

Greek philosopher Democritus believed that matter was indeed made of tiny irreducible parts that he called atomos, a Greek word meaning uncuttable. Without modern technologies, no one could devise a means of definitively settling the atomic debate. In fact, by 1900, many leading scientists rejected the atomic model of matter.

In 1827, English botanist Robert Brown made a seemingly unrelated discovery: when viewed under a powerful microscope, tiny pollen grains suspended in liquid move constantly and chaotically, without any apparent cause. For 78 years, no one could explain this mysterious Brownian motion.

Then in 1905, Einstein postulated that this erratic motion was due to atoms, too small to be seen in microscopes of the day, which continually collided with and jostled the much larger pollen grains. Einstein derived a diffusion equation that precisely predicted how Brownian motion varies with temperature, pollen size, liquid viscosity, and atomic mass. Meticulous experiments by French physicist Jean Baptiste Perrin confirmed Einstein’s predictions.

Einstein’s model and equation, validated by experiment, finally established that atoms really do exist and enabled the first measurements of their masses.

§1.3 Successive Approximation

In V1p1-1, Feynman stresses that our knowledge will always be "merely an approximation to the complete truth." This is in part because we do not yet know, and may never know, all the laws of nature. In addition, our instruments will improve, but will never achieve perfect precision. While perfection is likely impossible, continual refinement is expected.

What may be surprising, as Feynman emphasizes in V1p1-2, is that improved precision sometimes reveals tiny discrepancies, which can require dramatic changes in our models.

Consider an example in the theory of mechanics developed by Sir Isaac Newton (1642-1727). Before 1905, everyone believed that the mass of a body was the same whether it was moving or not. As Feynman said: people believed a spinning top has the same weight as a still one. The law was: mass is constant. Yet, Albert Einstein (1879-1955) said that law was wrong, mass increases with increasing speed — a claim confirmed by subsequent experiments. For normal speeds, the mass increase is extremely small, far less than the weighing precision of the day. For example, at 30,000 miles per hour, a body’s mass increases by only one part per billion.

One might amend the old law to state: mass is constant to one part per billion for all speeds below 30,000 miles per hour. The amended law is numerically correct, and after all, who moves that fast? But as Feynman says, that amended law is "philosophically completely wrong." The correct understanding is espoused by Einstein’s theory of special relativity, which revolutionizes our entire worldview.

Was Newton wrong? Perhaps it is better to say that Newton’s laws have a limited scope. For everyday activities, Newton’s laws are adequate for almost any purpose. But for more extreme conditions, we need the greater precision, and more importantly, the deeper understanding of Einstein’s relativity.

William Stoeger, a Ph.D. physicist and Jesuit priest at the Vatican Observatory, gave an intriguing lecture that I attended. The gist of his message was: science and faith are each never-ending quests for the least inadequate description of Truth. (How proud would you be taking home a report card saying you were the least inadequate student?) I cannot address how Stoeger’s statement relates to faith, but his description of science is correct. Science will always have unanswered questions, yet scientists have faith that we are inching ever closer to nature’s ultimate truth.

§1.4 Science Does Not Prove Theorems

Mathematical proofs are as close to absolute truth as humans can ever hope to achieve. In Euclidean geometry, the sum of the interior angles of any triangle equals 180 degrees. This theorem was first proven 23 centuries ago. It will be true forever and never needs to be proven again. Note, however, that this geometric theorem relates only to ideal triangles in an ideal planar geometry. There may not be even one real triangle in the entire universe whose angles sum to exactly 180 degrees.

By comparison, science is neither that clean nor that simple; absolute proof is impossible in science.

Scientific theories cannot be proven mathematically; they can only be validated by experiment. But experiments have limited precision and scope. No measurement of the mass of oxygen atoms will ever produce the correct value to an infinite number of decimal digits, and no one is going to measure the mass of every oxygen atom in the universe. Experiments can falsify wrong theories, but they can only validate models to a specified level of precision within a specified scope of conditions.

§1.5 How Best To Teach Science?

Since science is a progression of better ideas replacing less adequate ones, Feynman ponders the best way to teach physics. In V1p1-2 he says:

"Should we teach the correct but unfamiliar law with its strange and difficult conceptual ideas, for example, the theory of relativity, four-dimensional spacetime, and so on? Or should we first teach the simple ‘constant-mass’ law, which is only approximate, but does not involve such difficult ideas? The first is more exciting, more wonderful, and more