# Search results

1. ### Angles between vectors

Homework Statement From Analytical Mechanics by Grant R. Fowles & George L. Cassiday. Only problem I am having is with part d. Homework Equations ##A\cdot B = A_xB_x+A_yB_y+A_zB_z## ##sin(\theta) = \frac{|A\times B|}{AB}## The Attempt at a Solution I did it by hand but also ran the following...
2. ### Comp Sci Algorithm Optimization [Python]

Homework Statement Given a list of integers and a single sum value, return the first two values (parse from the left please) in order of appearance that add up to form the sum. sum_pairs([11, 3, 7, 5], 10) # ^--^ 3 + 7 = 10 == [3, 7] sum_pairs([4, 3, 2, 3, 4]...
3. ### I Logical Operators Assistance

While at university, we went over logical operators for our electronic circuits lab. There was one that depended on the previous value which fascinated my deeply, but for some reason I can't remember it. I only vaguely remember it so I apologize if I mess up what actually happened. From what I...
4. ### Non-Science Podcasts

I don't particularly enjoy Physics podcasts. Most science podcasts I've been subscribed to are just current science news podcasts I find extremely boring. I do enjoy Radio Lab and Hound and Tall by Moshe Kasher which are kinda like 60 Minutes. I also enjoy 60 Minutes podcasts lol. I like the...
5. ### Suggestion Physics Wiki/FAQ Section

I had this idea the other day on Arch Linux's wiki page. In that community, they have an extremely comprehensive wiki for learning and troubleshooting on your own in addition to a very active forum which is similar to PF now. The idea of have and FAQ section is an old one, but the best thing on...
6. ### Intel Distribution for Python

Hello, I am relatively new to Python. I would really like to use Python for numerical and data analysis. I recently stumbled upon something called Intel Distribution from this article: http://www.infoworld.com/article/3117239/data-science/intels-python-distribution-turbocharges-data-science.html...
7. ### Fiber Optic Coupling -- how to couple a 200μm core fiber into a 50μm core fiber?

Is it possible to couple a 200μm core fiber into a 50μm core fiber by using a 4x magnifier/reducer?
8. ### Aperature, Numerical Aperature and Speed of Lenses

I think I understand the relationship between the three, but I would like some feedback. I still am fairly unsure about lens speed and is what I'm mostly interested in. From my understanding: Aperture is the total diameter of the lens and numerical aperture is the ratio between the aperture and...
9. ### I Pie Chart Error Bars

Kind of a silly question; can pie charts have error bars? I have used x-ray dispersion to find the approximate chemical composition of unknown samples. Is it appropriate to have error bars on how much we expect the percentages to deviate statistically throughout the sample? Or, should I go a...
10. ### I Are White Dwarfs Stars?

Simple enough question, are white dwarfs stars? I know white dwarfs are the remnants of former stars, but is it correct to classify them as a current star? My understanding was that nuclear fusion was a deciding factor into whether or not an object was a 'star' and white dwarfs were void of any...
11. ### Animal Intelligence Distribution

My end goal is to extrapolate observed intelligences in the animal kingdom to determine whether or not it is statistically likely that a simulation argument is probable (though this could easily be used for the Fermi Paradox as well). Defining terms: "intelligence." Obviously all animals would...
12. ### I Milky Way's Globular Clusters

My question is directly towards figure 2.15 from Galaxies in the Universe, An Introduction by Sparke and Gallagher. Everything in the figure makes sense to me until the authors make the point, "Clusters with a blue horizontal branch (filled dots) are more concentrated to the center than are...
13. ### I Ionization and Nodes in the Hydrogen Wave Function

As you can see from figure 4.4 from Griffiths book on QM, the radial wave function of the hydrogen atom has clear points where ## |R_{nl} (r)|^2 = 0 ##. My question is three fold: First, how is the electron able to traverse this region? My intuition is that with the uncertainty principle, the...
14. ### Core Mass-Luminosity Relationship in RGB Stars

Homework Statement Low-mass stars like the Sun obey the core mass-luminosity relationship as they burn H in a shell and climb the RBG (Red Giant Branch). What is the energy released per unit mass when fusing hydrogen into helium? Homework Equations The core mass-luminosity relationship: ...
15. ### TDS2004B Oscilloscope Accuracy Determination

Hello, I recently did the Franck-Hertz experiment (a short summary of the experiment can be found here http://inpp.ohiou.edu/~roche/3701_web/man-fh-a3b.pdf). I am currently doing data analysis and am having a hard time determining the accuracy of the oscilloscope, the Tektronix TDS2004B. I am...