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visits member for 2 years, 11 months
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3h
comment Why do physics students find vectors so difficult to deal with?
This is a good answer, and is close to my own feelings as well. It's not that they "don't get" vectors - there's something about the abstraction of nature which they don't get.
3h
comment Why do physics students find vectors so difficult to deal with?
This is what I mean though - this is "teaching them" in the traditional sense, which doesn't stick. They write it down, remember it when you ask them 5 minutes later, but when you give them a problem they don't use the information you provided.
15h
comment Why do physics students find vectors so difficult to deal with?
I am absolutely talking about undergraduate education, and have changed the question to make that clear. There is no doubt they should know it already - I am mostly talking here about a (good, private) liberal arts institution, but I have experienced the same phenomena at research institutions as well. Of course, it wasn't as bad there...
15h
revised Why do physics students find vectors so difficult to deal with?
added 18 characters in body
15h
comment Why do physics students find vectors so difficult to deal with?
^^ Well, I decided to try it after looking around the other SE sites - which explains why there is one currently in definition.
15h
asked Why do physics students find vectors so difficult to deal with?
Dec
15
awarded  Nice Question
Dec
13
revised Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account?
clarifying my assumptions....
Dec
13
comment Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account?
The value for $C$ is different for our different cases, and that's my mistake. I'm assuming the bullet is falling like you dropped it horizontally - I'll correct it so the answer is clear in my assumptions.
Dec
13
comment Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account?
Well forces being different in different reference frames is not a problem. If it's "definitely the magnitude", then I think we need to know if the bullet turns while falling. Specifically, I agree that the drag force opposite the direction of motion should be dependent on the speed - but if the bullet doesn't turn while falling, then the drag force in the y-direction will be $C_yv^2$, whereas if it turns it will be $Cv^2sin\theta$, as in the other answer.
Dec
13
answered Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account?
Dec
13
comment Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account?
I do not think your first equation is correct. The drag force in the y-direction should only depend on the velocity in the y-direction, which is the same for both cases. I'll do another answer. I admit to not being an expert, perhaps we can reason it out.
Dec
13
comment Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account?
Now wait a second, you're not suggesting that the "v" in the formula for drag is the magnitude of the velocity, right? Because I'm pretty sure if I fired a bullet straight downward, the drag force in the horizontal direction would be zero...
Dec
12
comment What is the intuition behind “Net Work is Zero”?
kingkong5678: For a conservative force, doing work is just like changing potential. Since gravity is a conservative force, either is correct. However, when you lift something, gravity either does negative work on the system, or there is a positive change in the potential energy of the system.
Dec
11
answered What is the intuition behind “Net Work is Zero”?
Dec
8
awarded  Popular Question
Oct
25
comment Learning how to use Levi-Civita symbol
Oh also the first chapter of Landau's EM book has a footnote which contains some Levi-Civita stuff. I know that sounds obscure, but it's actually the first place I always go to when I need to know something about it!
Oct
25
comment Learning how to use Levi-Civita symbol
Maybe you need to look at an intro GR book - there is a lot more tensor calculus in such courses, so it will give you a better introduction. Check out the first couple chapters of Sean Carroll's review article: arxiv.org/abs/gr-qc/9712019, or the text that grew out of it.
Oct
18
comment Why doesn't topological phase transition break any symmetry? Hidden symmetry?
Not an answer, but just a clarification - we do not "assume" hidden variables do not exist. They have been proven repeatedly to NOT exist, unless the theory is nonlocal (Bell's theorem and experimental results). This is a strong constraint, in many people's opinion.
Sep
30
awarded  Explainer