I had this https://www.physicsforums.com/showthread.php?p=3200140#post3200140", which I posted on PF. I got the answer, but then I started thinking more about it and have some theoretical questions.
If you did have this particle of mass m in a box of length L, which you are trying to stop...
Homework Statement
A box of mass m = 4.5 kg rests on a larger box of mass M = 26.0 kg, which is at rest on a frictionless surface. The coefficient of static friction between the two boxes is μs = 0.51. An ideal string runs between the two boxes around a fixed pulley. What is the maximum force F...
The law says that the maximum thermal efficiency of a heat engine can be 88%.
If I have and internal combustion engine using 9.8 cc/min instead of 25 to 30 cc/min and the other accepted figure is a 2L 4 cylinder engine for idle is it uses approx 5 HP of fuel just just to idle.
So I am doing...
Suppose I am standing on the Earth surface and observing a rockhet of very high speed then i will see the length the rocket contracted and abserver on the rocket will also see my length contracted(I am not sure about it)in the direction of motion.
Is the same case takes place with time...
I am a sophomore at a Canadian University majoring in Mathematics and Computer Science. My overall GPA is 3.44 but I am hoping it to raise it to a 3.7 by the end of my junior year. I have heard that most undergrads apply for graduate schools at the end of their junior year. Since my GPA isn't...
As in, what if you have a VERY high voltage? Then I = V/R.
But what if you only have a limited number of charge carriers that could eventually run out? Then what will happen to the current? Will it suddenly stop following Ohm's Law? Will it immediately drop off to 0, or gradually drop off to 0?
Homework Statement
S is the balance of a savings account
W is the amount withdrawn per year.
k is a rate percentage of continuous interest per year
1. Solve the differential Equation above.
2. Draw a phase portrait and assess the solution's stability.
3. Assume you have $1,000,000 for...
In all the Abaqus manuals I have read, it only tells me what the pre-tension option DOES, or a little bit about how it works, but what I want to know is literally which buttons to press to get to that option and how to apply it. I can't find the option anywhere in the software.
Details of...
In all the Abaqus manuals I have read, it only tells me what the pre-tension option DOES, or a little bit about how it works, but what I want to know is literally which buttons to press to get to that option and how to apply it. I can't find the option anywhere in the software.
Details of...
Homework Statement
A jet of water having velocity v = 10m/s and stream cross section = 2cm^2 hits a flat plate perpendicularly, with water splashing out parallel to plate. Find the force that plate experiences.
density of water d=1000kg/m^3
Homework Equations
0.5dv^2 = p
The Attempt...
I am confused with some of the aspects of time dilation. I read the derivation (the one with the mirrors) and I understand it and it seems to make sense to me. In the usual derivation (http://www.drphysics.com/syllabus/time/time.html) , person A who moves with the apparatus (mirror-light...
Basically, the title says it all. I've never heard of Noether charge corresponding to gauge symmetry of the Lagrangian. Is it because gauge symmetry isn't the "right type" of symmetry (one parameter continuous symmetry) so the Noether theorem doesn't apply to it?
I am almost done with applying to graduate schools in mathematics. My new question now is whether to apply my undergraduate institution's graduate program.
First of all, all the professors that I have talked to told me that I should go somewhere else for graduate school. And I strongly agree...
I am a 2nd year student at BITS Pilani(India) and I am pursuing in mechanical engg. Since in India you don't have a lot of options other than engineering and my college has a good reputation here, I decided to opt for engineering. However, I don't have any real interest in engineering and I...
Everyone has heard that a butterfly flapping it's wings in one place may ultimately cause a tornado to form in another place. I really have a problem with this.
It has also been said that if all the molecules in a cup of coffee were to move the same direction at the same time that the coffee...
Homework Statement
Evaluate \int_0^1 \! \int_0^{1-x} \! \sqrt{x+y} \left(y-2x\right)^{2} \, \, \mathrm{d}y \, \mathrm{d}x. by applying the appropriate transformation.Homework Equations
N/AThe Attempt at a Solution
So far, the best I can come up with is u=1-x, v=x+y, which gives me \int_0^1 \...
Hello,
Thanks at first. If anyone can understand, then I would like to know how do I get to equation 4.15. Its a laplacian equation in which I want to apply the Fourier transform.
Thanks again.
This isn't a math question really, and I'm really sorry if I put this in the wrong section. Still, I've been going over fluid dynamics in class and I have a question about Pascal's Law. It may be silly, but it's one that's been kinda bugging me.
Pascal's Law says that any change in pressure of...
Hi! I am a 16 year old trying to figure out the application of taylor series. I understand most of its uses when applied to functions like e^x, sinx, cosx, but in a mechanics book, i am required to find delta-F, a finite change in a function F. Ostensibly, this appears to be a step that needs...
Hey there everyone.
I'm working on a project and I want to incorporate a small version of Faraday's Linear Shake Flashlight.
I'm stuck on how to apply Faraday's formula to the variables that I have.
The formula wants "flux". How to I calculate the flux of my magnets? I know the pull...
Just out of curiosity, how many graduate schools should a person apply too? I want to enter into a Ph.D or master's program in astrophysics. So far I have a relatively decent gpa, 3.8+, 4.0 in major. Summer internship with possible future publication, & I think my recommendations are solid...
I was wondering if this is correct:
\phi(k-a)=\phi(k)-\phi(a)
Where k=p/h (h bar that is) and a is some constant and \phi is the Fourier transform of a wave function (momentum function).
I know that if I had some real formula for \phi I could just test this but the problem isn't like...
I need a few safety schools, and most importantly a few target schools. I'll have no trouble coming up with reach schools.
The problem is that I have no idea what to look for. I know I want to do Physics, but that's the extent of it. I have no idea what part of physics I'd like to do, but...
I have about 10 schools that I'm interested in but I think that may be too many and maybe I should narrow it down to like 6 or 7. Is 10 too many or should I just go ahead and apply to all of them? Would applying to 10 schools take twice as much of my time as applying to 5 or would it just take...
[Two ball of mass 60g are attached with mass less rubber thread and held in vertical position as show in figure.
In this position length of rubber thread is 40cm and it is not stretched. The upper sphere is slowly raised vertically upward until the lower ball just becomes unsupported by ground...
A 10 kg mass is in free fall with no air resistance. In order to slow the mass at a rate equal to the magnitude of g, an upward force must be applied with magnitude:
F=ma
F=(10kg)(9.81m/s2) = approximately 100N
So in order to slow the mass at a rate equal to g it should be a...
I'm going to be entering senior year of high school this fall, and it's getting dangerously close to the time I'll need to begin sending out applications. The problem is, I'm not sure which schools to apply to. So far, my dream schools are Brown, Columbia and Williams. For some background info...
Hi all
I've got one more year left in my undergraduate degree at a Canadian university in physics. I'll be taking a year off after graduating before (hopefully) going to the US for grad school in synthetic biology. My question is, should I write the GRE and apply to grad school now and then...
Hi this is my first post on here
I am looking to create a large voltage across a primarily capacitive load at around 190 kHz. At the moment i have a 175 Watt power amplifier which puts out 55 Vp.
The output impedance also needs to be quite low < 100 ohms
Does anyone have any idea how to...
I am a senior in high school and I am taking a college class at a local community college. After this year, if I decide not to take the transfer credit, can I reject it? So I can take the course again at my new undergrad again?
Like basically abandon the transfer credit and grade? Will my...
I am a bit confused as to where I should apply for my undergrad. I know I definitely want to do pure mathematics, and I am looking at schools in the US (I am not from there). I do physics, math and further math at my high school as well as some personal work in my free time... what I want to...
I'm sure this is a question that comes up a lot but I can't find an old thread on it, and I've seen a lot of varying advice all over.
How many grad schools should I apply to?
Personally, I'm an junior (will be a senior in the fall) physics major with a 3.9 overall and about a 3.8 in math...
I am just wondering this because I have not set on what to do for graduate school. Now if I go for theoretical physics and study Math and Physics, when it is time for me to apply to grad school, will I get to apply to a math grad school or will they not let me because my major is "theoretical...
Hi everyone, I'm a newbie in this forum :) I have some questions regarding application for graduate study and need your help.
I'm currently a year 3 student and coming to final year of undergraduate life, majoring in Materials Science & Engineering. I'm considering apply for graduate schools in...
Homework Statement
y' + (2/t)y = cos(t) / t^2 initial cond: y(pi) = 0 ... t>0
Homework Equations
integrating factor is t^2
so.. integ (yt^2)' = integ cos (t)
= yt^2 = -sin (t) + c
y = ( -sin (t) /t^2 ) + c
..this brings up my first question.. when i divided through by t^2 to isolate...
Hi!
I have an array that is 1 column by many rows, of which each element represents a time. I want to find variable f at each time, where f is defined as follows:
if t < tp
f=(sin((pi*t)/(2*tp)))^2;
if tp < t < ts
f=(cos((pi*(t-tp))/(2*(ts-tp))))^2;
otherwise f=0
I've tried...
(to find distribution of sample mean)
Given
P((X1 - μ) / σ/√n) < Z < (X2 - μ) / σ/√n)) = P(a < Z < b) = phi(b) - phi(a)
where phi(z) = 1/sqrt(2*pi) * integral of exp(-z^2 / 2) dz from negative infinity to z
---
I'm sure there's some statistical way of doing this with a TI 89, but...
Reading about the Thermocouple:
http://en.wikipedia.org/wiki/Thermocouple
I came upon:
"...
Principle of operation
Main article: Seebeck effect
In 1821, the German–Estonian physicist Thomas Johann Seebeck discovered that when any conductor is subjected to a thermal gradient, it...
My physics teacher recently assigned this challenge and I have no clue where to begin. I think the ideal gas law might apply but I'm not sure. Any insight?
A bottle, full of air at atmospheric pressure, whose volume is 500 cubic centimeters, is sunken mouth downwards below the surface of a...
If I draw a random curve over a scalar field, then it is not generally true that the line integral of the scalar field over the curve equals the difference between the value of the antiderivatives of the scalar field at the beginning and finishing points of the curve, as one can clearly see by...
My calculus book says sometimes derivatives can be regarded as the ratio of differentials, and sometimes they can't. Apparently, there's a similar rule for integrals. When can I think of derivatives and integrals as operations with differentials? And when can't I?
Hey guys,
I'm currently a sophomore chemical engineering major and I'm looking to do an REU related to physical or organic chemistry, or chemical engineering applications. I know most people here would be math or physics or other engineering majors, but I'm just wondering if anyone who had a...
http://mail.google.com/mail/?ui=2&ik=73e979647b&view=att&th=125926df4ffe1738&attid=0.1&disp=inline&realattid=f_g25eq5it0&zw
This is NOT homework.
In the FBD above, there is no friction, the velocity is constant, and the distance traveled by the box is 10 m horizontally. Find the work...
Applying it to
-x2 - bx +c = 0
I would have thought it to be
(b +- (b2+4c)0.5) /-2
= (-b +- (b2+4c)0.5) /2
But
Anytime I try and graph a function like it the roots are
(b +- (b2+4c)0.5) /2
I can't see why this is?
Thanks
Homework Statement
A cylindrical bucket of liquid (density ρ) is rotated about its symmetry axis, which is vertical. If the angular velocity is ω, show that the pressure at a distance r from the rotation axis is
P = P_0 + \frac{1}{2} \rho \omega^2 r^2
where P0 is the pressure at r = 0...