Recent content by John Morrell

Do you mean that the direction, like the unit vector of the x y and z momentum, is unchanging (unless of course the particle interacts with something else)? The direction it travels is essentially constant?

Okay, this is a question that's always kind of bothered me. According to dozens of articles and interviews with NASA employees or professional astronomers, one of the biggest dangers of long term space travel is the bone and muscle loss. That totally makes sense; being in zero G is even worse...

There are a couple things that I'm unclear about. What do you mean when you say 'energy'? Do you mean the potential energy of a particle far away from the sphere? This seems a bit unclear. Also, I'm assuming for the first part that you are measuring the potential difference from infinitely far...

The reason this problem is tricky is that, obviously, both x^3 an e^x approach infinity as x approaches infinity. But in this case, not all infinities are born equal. Some are more infinite than others. If you know that one of these functions is larger than the other, and remains larger, than...

Hey thanks for the help guys! In a way this sort of this is kind of maddening because I'm actually an engineering student and I don't know if I'll ever have time to really thoroughly understand this sort of thing in the way that a real professional course of study would let me. But It's nice to...

I've recently been doing some learning about the double slit experiment and a bit about how, qualitatively, quantum electro dynamics works. Something that I wondered about for a long time was how momentum could be conserved in these systems when we assume that a particle could land in any number...

I'm not sure what you mean by your second question, but is it possible that you're measuring the Earth's magnetic field? That would give you a non-zero value for a zero current. The Earth's magnetic field ranges from about 25-65 micro teslas, which seems large enough to account for the error...

Okay, mind slightly blown. Also thanks for telling me about that category; somehow I didn't see it when I posted.

The way that calculus generalizes to other things is incredibly cool. When you get a chance, make sure you learn multi-variable calculus and stuff like that. Triple integrals and unit conversions are so fun.

I feel your frustration and it really seems like you do want to do physics for a great reason; you want to understand stuff and you want to learn and you're willing to work hard. But there are some hard truths you need to face. You can't change the professor. You might go the department and...

Look, the only way to always be right on a problem is to make no mistakes. If you got a wrong answer then you made a mistake. That might just be because you accidentally put something in a calculator wrong, or it might be that you have an incorrect or incomplete understanding of the theory. If...

Since the universe is expanding, photons emitted by distant stars are red-shifted, having their wavelengths stretched out. But, since the energy of a photon is dependent on the inverse of its wavelength, doesn't that mean that the expansion of the universe is causing photons to lose energy? How...

Okay, cool. I was in the process of asking why the universe couldn't be finite with a center and then I realized that that had already been answered. Thanks!

Perspective is just another way of saying reference frame, it's not really anthropomorphizing anything. I mean, is it anthropomorphization to calculate the Earth's reference frame? Also I don't understand why we can't define a rest frame for light. It's not accelerating (at least as long as it...

exactly. The main skill in doing integrals like that is to accurately find your infinitesimal quantity. It might be a tiny force or a tiny mass or a tiny length, but it can't be zero. It just has to approach zero. That's why it's so helpful to think of integrals first as Riemann sums, where we...