Category Archives: physics

TweetChapter 7 Exercises I just finished working all the odds here. That is, I did a homework assignment from hell. That said, it’s always an excellent refresher. I’m (generally) selecting one problem from each subsection that was clever or difficult. … Continue reading →

TweetDiscussion Questions in Chapter 7 Q7.1 “A baseball is thrown straight up with initial speed . If air resistance cannot be ignored, when the ball returns to its initial height its speed is less than . Explain why, using energy … Continue reading →

Tweet7.5: Energy Diagrams Kids, graphs are magic. Graphs are magic because your fancy monkey brain is very visual. So, with a little training, a graph can tell you a lot of information about a system in high detail at a … Continue reading →

Tweet7.4: Force and Potential Energy If you’ve been following along with calc, this should be relatively easy. Here’s the idea: Force is the derivative of potential energy, with respect to position. Mathematically, that’s: F(x) = dU/dx. This makes sense, since … Continue reading →

Tweet7.3: Conservative and Nonconservative Forces All “real” forces are conservative. That is, for the purposes of this text, if we’re talking about abstract systems containing only (a) GRAVITY or (b) ELECTROMAGNETISM or © BOTH, shit is simple. However, when we … Continue reading →

Tweet7.2: Elastic Potential Energy Out of habit, I’m going to refer to this idea as “spring energy.” This is one of those really cool sections where, in a couple pages, you get a concept that changes the whole way you … Continue reading →

Tweet7.1: Gravitational Potential Energy We’ve already discussed the idea of conservation of energy, which is one of the most important concepts, not just in physics but in reality. When thinking about whether someone is bullshitting you, one of the best … Continue reading →

TweetSupplementary Exercises in Chapter 6 BRING ON THE PAIN. Maybe it’s just because I’m a little rusty on integrals, but these beat me up a bit. BUT, now that I’ve solved them I’m feeling a bit more confident. As with … Continue reading →

TweetSection Exercises in Chapter 6 These problems weren’t so tough. At least to my brain, work-energy stuff is fairly intuitive. 6.5 “A 75kg painter climbs a ladder that is 2.75 m long leaning against a vertical wall. The ladder makes … Continue reading →

TweetDiscussion Questions in 6.4 Because the problem sets in this book are very long, I think I’ll chunk them into discussion, then section-based exercises, then the rest. Q6.1 “The sign of many physical quantities depends on the choice of coordinates. … Continue reading →