Physics! #1 – University Physics 1.1

I’ve decided to call this series “Physics!” instead of science, so as to differentiate when I also study other areas concurrently.

For this series, I’ll be using the new edition of the book I used in college. It is “Unversity Physics,” 13th edition, by Young and Freedman. It’s a fairly standard intro physics text, the only downside being that it doesn’t contain much calculus. But, as my friend Tony Piro said of calc-free physics books, “it’s good for developing intuition.” So, let’s get some of that.

Section 1.1: The Nature of Physics

In this brief section, we get a definition of “Theory,” which presumably exists thanks to the ongoing argument with creationists over whether a word can have different meanings in different contexts.

As an example, they present Galileo’s famous ball dropping experiment. I consider this experiment to be one of those works of fine art that we have lost the ability to appreciate because it is so well known in our culture. In the same way as it is difficult to appreciate Mozart’s Eine Kleine Nachtmusik or Leonardo’s Mona Lisa, it is hard to appreciate how truly bizarre this experimental result is. I still have difficulty wrapping my head around it. All these objects with different mass somehow¬†accelerate at a certain speed that depends on gravity.

Having gone a bit further in physics than this, I feel like I have a somewhat more in depth knowledge of the topic, and yet I don’t really feel like I understand it. But, I suppose that’s the fun of learning physics. Perhaps by the time we get to the end of Quantum Mechanics, I’ll feel better about myself.



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6 Responses to Physics! #1 – University Physics 1.1

  1. Morris Keesan says:

    Wasn’t Galileo’s “ball-dropping” experiment actually a ball-(or cylinder)-ROLLING experiment? I’ve heard, or read, that despite the popular image of him dropping things off the tower of Pisa, what he actually did was to roll objects, of different weights but equal size, down an inclined plane.

  2. Stephanie says:

    In my experience, studying quantum mechanics is accompanied with feelings of joy and new levels of inadequacy.

  3. Joshua says:

    One of the staggering things about general relativity is that it gives a real explanation for this! Objects go in straight lines in curved spacetime, so their paths don’t depend on their mass at all. Gravity isn’t really even a force! Now the mystery is why this explanation gives almost the same predictions as Newtonian gravity.

  4. Steuard says:

    I quite dislike the way that most intro physics textbooks start out. This sort of “philosophical and historical background” is awesome and a good entry point to the subject, no question, but 99.84% of students actually taking the course skip right over it because it’s not on the homework. I much prefer the rare books that plunge into basic problem solving (while sneaking in the history and philosophy along the way). I’m currently teaching out of Knight’s book, which takes that approach.

  5. Adam Glesser says:

    Check out some of the videos on
    In particular, the ball dropping experiment shows up:
    The videos are very nicely done, with predictions by random people thrown in.

  6. tussock says:

    Joshua’s got it. In the real world it’s us, stuck on the surface, who are accelerating at a constant rate of change, and all those “falling” objects which are not. Their acceleration appears to be the same because they aren’t accelerating at all, we are.

    Feel that chair pushing at your butt? *That’s* acceleration. We just look at the wrong frame of reference all the time, because our brains are made of monkeys.

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