# Search results

1. ### Change in the amplitude of a damped spring block oscillator

Homework Statement A block is acted on by a spring with spring constant k and a weak friction force of constant magnitude f . The block is pulled distance x0 from equilibrium and released. It oscillates many times and eventually comes to rest. Show that the decrease of amplitude is the same...
2. ### RC Circuit with parallel resistor

Thank you so much! Couldn't visualise what was going on for the longest time but it really does make sense now.
3. ### RC Circuit with parallel resistor

Fair enough I understand that part. What seems counterintuitive to me is that a current starts flowing in R1 just by introducing a new resistor. Why?
4. ### RC Circuit with parallel resistor

Here's a picture of the circuit. It is still in parallel with the resistor and the power supply. I don't understand why it is isolated, although, if it was I suppose the voltage across it would be the same as it was when it was initially fully charged, i.e = E.
5. ### RC Circuit with parallel resistor

Homework Statement A circuit contains a capacitor of capacitance C, a power supply of emf E, two resistors of resistances R1 and R2 , and a switch S2 . Resistor R1 is in series with the power supply and R2 is in parallel with the capacitor and the power supply. S2 switches the branch that...
6. ### MATLAB Help: Convert Matlab to Python code

I've had a couple of issues while translating the code. 1.In the line "That = ODhat*V(:,2:3);" I get matrix multiplication errors when I use numpy matmul. Say my input is a 10X10X3 RBG image for simplicity. We flatten it to 100X3 rgb value. After removing any transparent pixels, let's say it...
7. ### MATLAB Help: Convert Matlab to Python code

Alright so I'm stuck at this line: % remove transparent pixels ODhat = OD(~any(OD < beta, 2), :); I'm not even entirely sure what this does. What does the 'any' and the 2 stand for? How would i write this in python?
8. ### MATLAB Help: Convert Matlab to Python code

Could I run the function as it is using matlab.engine on python? Image to numpy array which I then feed into the function? Will MATLAB recognize a numpy array as a matrix?
9. ### MATLAB Help: Convert Matlab to Python code

Thank you! @scottdave and everyone else. I think I am going to try translating it semantically on my own.
10. ### MATLAB Help: Convert Matlab to Python code

I'm working on a convolutional neural network project that classifies histopathological images of breast tumors. All my code is in python. Part of the image preprocessing involves appearance normalisation to account for the variation in histological staining. The only code for the preprocessing...
11. ### Relationship between magnetic moment and induced magnetism

How would you calculate the induced magnetic field B at some distance R from a bar magnet, given the magnetic moment of a magnet? (In general)
12. ### Cambridge NSAA Question -- Measuring the speed of sound with a speaker and 2 echos

Sorry about the title, the “measuring the speed of sound” part was added by a moderator for ‘not being descriptive enough’. Not my doing.
13. ### Cambridge NSAA Question -- Measuring the speed of sound with a speaker and 2 echos

Homework Statement This is a problem from the Cambridge Natural Science Admissions Assesment. A student carries out an experiment to measure the speed of sound. A loudspeaker that emits sound in all directions is placed between two buildings that are 128 m apart as shown. The student and...
14. ### Oscillation of a point charge perpendicular to field lines

I understand the dimensionality argument. How and why does the force depend on the charge separation though? Wouldn’t those components cancel each other out?
15. ### Oscillation of a point charge perpendicular to field lines

Homework Statement Two particles A and B each carry a charge Q and are separated by a fixed distance D. A particle c with charge q and mass m is kept at the midpoint of A and B. If C is displaced perpendicular to AB by a distance x where x<<<D, find the time period of the oscillation of the...
16. ### A Symplectic geometry of phase space

Thank you, this is the most concise explanation I've seen yet!
17. ### A Symplectic geometry of phase space

What is a symplectic manifold or symplectic geometry? (In intuitive terms please) I have a vague understanding that it involves some metric that assigns an area to a position and conjugate momentum that happens to be preserved. What is 'special' about Hamilton's formulation that makes it more...
18. ### Machine learning / AI - Where do I start?

I am a programming novice with minimal knowledge of C, Python and Java that I've taught myself from books and videos. Eventually I'd like to get into AI and machine learning but I have no idea where to start. Thus far, the minimal coding I've learned has been rather aimless with no specific...
19. ### I Hamiltonian as total energy for natural systems?

Could someone please prove that the H=T+V for systems where the transformation from Cartesian to Generalized coordinates is time independent. I have read through the proofs in Taylor's classical mechanics and Goldstein's but do not understand them.
20. ### Project Euler solution 3

My apologies, i meant 6857. My program generated the correct answer. Admittedly I'm not too sure why and i don't know why it doesn't work when i try x*x<n. Also, i meant to print factor, not x.
21. ### Project Euler solution 3

I've just started with project Euler. The problem I just finished is phrased as follows: "The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ?" The method i used was trial division. Here is my code in C: #include<stdio.h> int main() {...
22. ### Why don't we feel the Earth's rotation?

So are Newtons laws an approximation on earth?
23. ### Why don't we feel the Earth's rotation?

Pardon me if this seems like an incredibly naive question. Perhaps the question could also be rephrased as such: "Why do the laws of classical mechanics hold true with Earth as a frame of reference?" A quick google search turned up the usual answer: the Earth rotates at a constant speed...
24. ### Virtual work and D'alembert's principle

Oh alright, thank you nonetheless!
25. ### Virtual work and D'alembert's principle

Thank you! I'm starting to get a sense of what these actually mean. Thus far I have just seen derivations and statements of both principles. Thank you! Thus far I've only seen insipid derivations and statements of both principles but I think I'm starting to understand what they actually mean...
26. ### Virtual work and D'alembert's principle

I can't for the life of me figure out what virtual work or D'alemberts principle mean and what the intuition behind them is. As far as I'm concerned D'alemberts principle is just a restatement of Newton's second law but considering the work instead of just the forces. What am I missing? I'm...
27. ### I Limits of integration on Polar curves

The area enclosed by the Polar curve using Int(1/2 r^2) d theta. I find the determination of the limits of integration slightly ambiguous when I watch any tutorials or read up on Polar coordinates. I normally just use graph trace but I'd like to get an intuitive understanding
28. ### I Limits of integration on Polar curves

Oh sorry, any closed curve defined in Polar coordinates. Cardiods, limacons, circles, the works.
29. ### I Limits of integration on Polar curves

General question, how do you determine the limits of integration of a polar curve? Always found this somewhat confusing and can't seem to find a decent explanation on the internet.
30. ### AP Calculus BC: Differentiability and continuity

Ohh so if I'm not mistaken, we are simply trying to find a possible function that doesn't satisfy 1 &3 but could possibly satisfy h(x)=h(2-x) Thank you so much for your time and help! :)
31. ### AP Calculus BC: Differentiability and continuity

Alright i follow that logic except for how h(x) = -1 satisfies h(x)=h(2-x) If h(x) = -1 how do we know this implies h(2-x)= -1 Doesn't the condition hold for only a specific function and not any i choose?
32. ### AP Calculus BC: Differentiability and continuity

Any negative number? Say h(x) = -1 If so, aren't we assuming the value of h(x)? How can we say for sure
33. ### AP Calculus BC: Differentiability and continuity

I'm afraid I don't follow. Wouldn't it have to be a constant function for the derivative to be zero? Why is important that the derivative of this counter example must be zero?
34. ### AP Calculus BC: Differentiability and continuity

Okay so h'(1)=-h'(1) 2h'(1) = 0 h'(1) = 0 Is this correct?
35. ### AP Calculus BC: Differentiability and continuity

Phew, alright i think i get that part. Consequentially I understand we can eliminate condition 3 because h'0 will be -h'(2) and not h'(2) and also there is no way to say they are equal to 1 (Hope I'm right). How do you deal with the first condition though? I see no way to test the value of the...
36. ### AP Calculus BC: Differentiability and continuity

Unless this always implies that h'(x) = 0? Is this reasoning correct?
37. ### AP Calculus BC: Differentiability and continuity

h'(1)= -h'(1) ? How does this make sense?
38. ### AP Calculus BC: Differentiability and continuity

I'm confused. According to the chain rule its the derivative of the outer function X the derivative of the inner function. Doesn't that give h'(x) = h'(2-x)(-1)?
39. ### AP Calculus BC: Differentiability and continuity

Also, I'm a bit lost as to how i would test the first condition, Inorder to do so wouldn't i need to know that h(x) lies mostly or wholly above the x axis?
40. ### AP Calculus BC: Differentiability and continuity

I tried using the chain rule. What i get is h'(x) = h'(2-x) (-1) = -h'(2-x) When evaluated at x=1 thos gives h(1)= -h(1) which makes no sense to me
41. ### AP Calculus BC: Differentiability and continuity

Homework Statement The function h is differentiable, and for all values of x, h(x)=h(2-x) Which of the following statements must be true? 1. Integral (from 0 to 2) h(x) dx >0 2. h'(1)=0 3.h'(0)=h'(2)=1 A. 1 only B.2 only C. 3 only D. 2 &3 only E. 1,2 &3 Homework Equations None that I am...
42. ### Help: Physics vs Engineering Physics vs EE / ME

I'm a final year high school student trying to figure out what he wants to study in university. I have decided on an applied math double major with one of the above. My dilemma is between deciding to purse the passion I have for theoretical/ pure physics or an applied science as I would really...
43. ### Co-ordinate plane rotation

cos (α + β) = cos α cos β − sin α sin β sin (α + β) = sin α cos β + cos α sin β Using this, I can write, x'=rcos theta cos phi - sin theta sin phi and y'= rsin theta cos phi + cos theta sin phi and x= rcos phi y= rsin phi Now what do I do?
44. ### Co-ordinate plane rotation

The last sentence is actually y'. Sorry
45. ### Co-ordinate plane rotation

I understand that x' = rcos(theta+phi) and y'= rsin(theta+phi) and that x=rcos theta and y= rsin theta. How do I use this to get x'= xcos theta + ysin theta And y= -xsin theta + ycos theta
46. ### Co-ordinate plane rotation

Angle addition formulas for what? I don't understand you fully :(
47. ### Co-ordinate plane rotation

If I have a point (x,y) and I rotate the axises by some amount. Why is x' = xcosθ+ysinθ and y'=-xsinθ+ycosθ?
48. ### Velocity Profile

What is a velocity profile in fluid mechanics? Why do they give you a ratio between the fluids velocity and a random reference velocity and why is it equal to a completely arbitrary function? Does the ratio equal a function because it is an experimental fact?
49. ### Complex Vector Space Analogy To Quantum Mechanics

Thanks Guys... I am kinda getting an intuition on why complex vector spaces are used instead of real ones. But i think its really weird that operations that you would do with classical vectors or pointers work with elements of a set.
50. ### Complex Vector Space Analogy To Quantum Mechanics

Yeah, but I haven't learned complex vector spaces and how can we perform real vector operations on abstract vectors?