I know that its for boosting minorities in physics & not for giving people with other issues a chance. However I didn't fit purpose and applied anyway. A masters program from here took me in. Just saying it could be an option after he strengthens his foundation. Although the above program does...
Ok thanks! I'll definitely contact him. Another question. I'm looking to transfer there because it seems less competitive than say, Harvard/Columbia. Also, if I do get there and work under him, since he's a world-renounced researcher (one of the highest cited in world), it seems that having his...
I didn't contact him yet. I think that since he's busy (he's one of the highest cited scientists in world has 15 grad students and is professor emertus at Berkley), he won't have time or my just tell me to just apply. Should I still contact him? Other options?
Hello,
I'd like to work in the above named center at the University of Georgia in Athens, Georgia under Dr. Henry Schafer. However, he's a professor in the chemistry department. I'm guessing if I go in the university as a physics graduate student I can't have him as a Ph.D advisor. However, is...
Oh I forgot something:
df/dx = f'(x+vt)*dx;
df/dt = f'(x+vt)*v*dt
So KE + PE = μ/2[(f'2(x+vt)*dx+v2*f'2(x+vt)*dt] = 0.5*μ*(1+v2)*f'2(x+vt)*(dx+dt)
Forgot to add primes in front of f's to indicate derivative.
df/dx = f(x+vt)*dx;
df/dt = f(x+vt)*v*dt
infinitesimal energy = KE + PE = μ/2[(f2(x+vt)*dx+v2*f2(x+vt)*dt] = 0.5*μ*(1+v2)*f2(x+vt)*(dx+dt)
Total energy = ∫0.5*μ*(1+v2)*f2(x+vt)*dx I'm guessing dt goes to zero since we're integrating with respect to space/over entire spring & not time. Is this...
Ok, so I figured out that dψ/dx = dψ/dt. So infinitesimal energy = μ/2(2V2*(dψ/dx)2)dx. Since v2 = T/μ, infinitesimal energy = T*((dψ/dx)2)dx. Now I integrate to get total energy for whole string: total energy = ∫T*((dψ/dx)2)*dx. Limits of integration are ±∞. I don't see how they go from this to...
Homework Statement
There's a string with tension T & mass density μ that has a transverse wave with ψ(x,t) = f(x±vt). f(x) is an even function & goes to zero as x→±∞
Show that the total energy in the string is given by ∫dw*T*((f'(w))2; limits of integration are ±∞
Homework Equations
The...
The Attempt at a Solution
1) ∫-∞ ∞δ'(x)*f(x-a)
2) = ∫δ(x)*f(x-a)dx-∫f'(x-a)*δ(x)dx
3) = f(-a) - f'(-a)
Went from 1st to second by integration by parts
Used integral definition of delta function to go to 3rd part
Made above easier to read
Homework Statement
Prove the following
'()( − ) = −′()
∫-∞∞δ'(x)*f(x-a) = -f'(a)
Homework Equations
∫-∞∞δ'(x-a)*f(x) = f(a)
The Attempt at a Solution
[/B]
∫-∞ ∞δ'(x)*f(x-a) = ∫δ(x)*f(x-a)dx-∫f'(x-a)*δ(x)dx = f(-a) - f'(-a)
Went from 1st to second by integration by parts
Used...
Homework Statement
https://1drv.ms/b/s!ApJAu5EMYb4JgpYy68UWlGVzp0PVLQ
Problem 21
Homework Equations
[/B]
x1 = Aeiw0t + 3Be2iw0t
x2 = 3Aeiw0t - Be2iw0t
The Attempt at a Solution
[/B]
At t = 0 both masses at equilibrium so the above equations simplify to:
0 = A + 3B
0 = 3A - B
Thus B =...
Oh! I was just guessing. I forgot to tell you, I basically solve this using loop current method & current equalities. Here's a link to my teacher's answer if it'll help.
https://1drv.ms/b/s!ApJAu5EMYb4JgpYqh2SQVlgB1Tevvw
Wow, it seems the replies imply that you are not given enough support from the school for this class. Out of curiosity, does this happen a lot in your school district & in the U.S.A in general? If what I said about support is true & curriculum is undoable, maybe ignore the entire curriculum &...
https://1drv.ms/b/s!ApJAu5EMYb4JgpYy68UWlGVzp0PVLQ -- Here's the link if it helps you see better. problem 18b.
I would not assume anything is equal to another unless the problem explicitly says that
So this means that we can't use their complex form because whatever operators we use on them are only linear? Also, is another way to understand this is that since power & voltage are real, that means we must take their real part when doing operations with them?
Yes, I know that they plugged in Q(t) = Aeiwt into the differential equation & found A. Then they took Re(Aeiwt) & plugged that into energy equation for part a. I still don't understand this: Why can't you plug in Aeiwt into the energy equation as opposed to its real part?
Homework Statement
Just help me with 18 b.
Homework Equations
V1 = c1I1Z1. Same for V2,3,45. V = V1+V2+V3+V4+V5. V/I=Z=impedance.
The Attempt at a Solution
Maybe because of symmetry Z1=Z2 & Z3=Z4. Perhaps Z5 takes out one of the branches? Can I get a hint?
I'm not doing any internships either. For the summer I'm doing the following:
1) Doing a sales/marketing job. I'm going door to door & setting appointments for doors,gutters, etc. Money os good, but as a poster alluded to, soft skills are important. I'm developing marketing/communication skills...
Well in the answer the teacher gave, he took the real parts of Q(t) & dQ/dt. He then plugged them into the E formula above. Why does this work and my approach doea not (I take the real part AFTER equations are plugged in).
Homework Statement
Homework Equations
Q(t) = Aei(wt+Φ); dQ/dt = i*w*Q(t); E = (L/2)(dQ/dt)2 + Q2/2C
i = √-1 E above is average energy
The Attempt at a Solution
When I plug in Q(t) & dQ/dt into equation above (E) I get:
A2L/2(w02-w2)cos[2(wt+Φ)]
w02 = 1/LC
After I plugged both of them in...
Homework Statement
Lets say f(x) is a solution to TISE. If it is, why is its complex conjugate f*(x) a solution too?
Homework Equations
TISE = time independent Schrodinger equation
The Attempt at a Solution
?
=So for A1, let's say that the charge is closer to that than A2. Because E1=(charge density *A1)/R1^2 and E2=(charge density *A2/R2^2). We can say that magnitude E1=magnitude E2? So for A1, even though the charge is closer to that area, A1<A2. For A2, even though the charge is farther away from...
Homework Statement
If a point charge is inside a Gaussian sphere but is off center, why is its electric field still Qenc/(e0*4*pi*r^2)?
Homework Equations
surface integral of E*da=Qenc/e0
The Attempt at a Solution
If we draw cones out from the charge. the 2 surfaces from the cones'...
But since you don't have the right answer, you don't know if the equations you derived are right. So, how can you know if you have the right approach to begin with?
The end of the chapter things are divided into 2 sections:
1) Problems-these have detailed solutions
2) Exercises-these have no solutions whatsoever
this helps?
The main question I have is if it's worth doing the exercises (#2 above). Since they don't have the answers in the back, is it...
So you're saying that I should do the exercises that deal with the same subject as the problems I was struggling with. But, how do I know if I' got them right? There's 33 problems (with soln) and 50 exercises (w/o soln).
Hi everyone,
I'm studying E&M using Purcell & Morin's textbook. The end of chapter exercises are divided into problems (has detailed solutions) and exercises (no solutions whatsoever). I know I should do all the problems, but is ti worth it doing the exercises. I mean, if I try the problem...
Homework Statement
y=[(1+y^2)^1.5]/[2(y+sqrt 3)^2]; solve for y
Homework Equations
see above
The Attempt at a Solution
I tried to use algebra to solve it, but I can't. The textbook says it can be solved numerically or by iteration. By numberically I think it means algebraically. But I don't...
Ok, but it says this book is for juniors and seniors taking intermediate level e&m. Is there any textbook as rigorous as the one I mentioned and is for freshman/sophomore level e&m?
Please help me find a similar textbook to the one below. Note that I'd like it on the internet and free. Thanks!
"Electricity and Magnetism", E. Purcell & D. Morin, 3rd edition. From what I've heard, it's a textbook for an introductory electricity and magnetism class. Note that it has some...
The reason I ask this is because I met with my advisor this week. He told me that if I want to go to grad school, taking just the required class and getting As is better than adding a minor or double major and getting Bs. Is this true? The answer to this will determine how I select my classes at...
Which is better:
1) Majoring in physics, minoring in computer science, and getting Bs and some Cs
2) Just majoring in physics and getting As and some Bs.
Also, how do you pay for grad school? If your're accepted in gradschool, do they pay for your living and tuition, or do you have to pay for...
What this user said definitely resonated with me. Maybe I should look into the past to answer my questions. Years ago, I was doing mental math. I was trying to figure out how to multiply 23*67 in my head for instance. Recently I figured out that 23*67=(20+3)*(70-3). After years and years of...
correction
Shoot! I'm sorry! T=r*F. I got it backwards! If I plug in the right equation, the first equation will eventually turn into 0.5*m*(r^2)*(ωf^2)=I*(ωf^2).
response to ehlid
How is it wrong? Force is torque times radius, is it not. Oh, I can't use scalar multiplication on this. Do I have to use the cross product: F=t x r?
Homework Statement
How to derive W=(.5*I)*((ωf^2)-(ωi^2)) from W=τ*(θ)
Homework Equations
The two equations seen above (big W is work; little w is rotational velocity, τ is torque, alpha=rotational acceleration).
s=r*θ a=r*(alpha) (ωf^2)-(ωo^2)=2*(alpha)*(θ) F=r*τ F=ma...
response
I guess you need to watch someone life weights to learn the technique. However, at some point you have to lift weights. I guess you need both, but mostly #1.
I am doing #1. However, my question is which is the correct way to do #1. Is spending hours and hours on a single problem...
replying
Ok guys,
Thanks for your posts! The reasons is I sometimes spend 2-3 hours on a single problem (in physics 1: classical mechanics). I sometimes think that those hours are wasted b/c I've heard spending hours and hours on a single problem is time gone down the drain. Based on my own...
Which is a better way to do physics?
1) Do a complicated problem, spend hours and hours on that single problem until you solve it.
2) Try to do the complicated problem for 5-10 minutes; look at the answer and try to understand the answer for 5-10 more minutes. Then, move onto another...
question for lazer
So, basically you (thegreenlazer) mean this:
Let's say that you're examining what the initial height of the ball was when it was falling due to gravity. What happens to it. Initially, it has potential energy. As it falls, that potential energy turns into kinetic until all...
question for lazer
So, basically you mean this:
Let's say that you're examining what the initial height of the ball was when it was falling due to gravity. What happens to it. Initially, it has potential energy. As it falls, that potential energy turns into kinetic until all the energy right...
other ways
Alright, thanks. It looks like I'm on the right track. Can someone tell me of other ways to build a conceptual understanding of physics besides doing problems?
Thanks