# Search results

1. ### Berkeley physics course

I wanted to do some physics over the break, electricity and magnatism to be exact. I have already taken the course so im not going through the material for the first time, I have also take vector calculus. The book I wanted to buy was Electricity and Magnetism, Vol. II by Berkeley Physics I...
2. ### Help integrating

the question is "evaluate \iiint z \,dv, of a solid tetrahedron bounded by the four planes x=0,y=0,z=0, and x+y+z=1" I can set up the problem correctly but i cant seem to integrate it right \int_{0}^1 \int_{0}^{1-x} \int_{0}^{1-x-y} z dzdydx (1/2) \int_{0}^1 \int_{0}^{1-x} (1-x-y)^2dydx can...
3. ### Gauss's Law and a conducting sphere

"A solid conducting sphere with radius R carries a posative total charge Q. The sphere is surrounded by an insulating shell with inner radius R and outer radius 2R. The insulating shell has a uniform charge density \rho a) find the value of \rho so that the net charge of the entire system is...

I was a bit confused by a homwork problem that I was working on. The problem is that I found the flux of a charge and I know the demsions of the Gaussian surface it is encolsed in. It doesnt seem right intuitively to be able to find the location of the charge from this information....but...
5. ### MATLAB MATLAB confusion

Hello all, i am trying to write a script file that will only print if R is divisible by D where D=3 I wrote a loop statement with the condition being fix(R/D)=R/D this works fine but there is another way that the book does it. The book uses mod(R,D)=0 as the condition. I tried typing in help...
6. ### What about the z's ?

what about the z's ?? I am a physics major in my second year and I wanted to know how other physics/engineering students manage their sleep. Basically I was wondering how other students sleep patterns are and how it works out for them.
7. ### Course called scientific and engineering computation

course called "scientific and engineering computation" I am taking a course called "scientific and engineering computation" using the MATLAB program and I was just wondering where should I post questions on this topic?
8. ### Would the friction be in the plane?

If you had two disks with the lower one rotating and dropped the one on top onto it they both come to the same angular speed b/c of friction. How come there is no torqu action on it? Would the friction be in the plane?
9. ### How long does it take for rotating platform to stop

Hi my problem is I have a platform that is rotating and it \omega_0=8\pi and the question is how long does it take it to stop. All my work up to here is correct and I have \sum\tau=I\alpha where my \sum\tau=3.75Nm and I=1.91kgm^2 and \alpha=1.96rad/s^2 so I wanted to use the \omega=...
10. ### Pfoof of e^x

I was looking at my math text and I saw that e^x=\sum_{n=0}^{\infty}\frac{x^n}{n!} and it sugests that you prove it to yourself. So this is what I dont get if f(x)=e^x=\sum_{n=0}^{\infty}\frac{x^n}{n!} then \frac{d}{dx}f(x) should equal that..now im not qeustioning that its true im just having...
11. ### Linear density

I had a problem with finding the moment of inertia. I have a rod and it has linear density\lambda=4.0kg and the equation for its moment of inertia is I=\frac{1}{12} ML^2 now I have an axis at the center of mass of a rod the rod has a total length L=4m so in my equation I would have to substute...
12. ### Concept of conservation

I had a conceptual question. Say I have a ball and I throw it against the wall and it bounces back. I have initial values for its velocity but not for the final velocity using the \vec{P}=m\vec{v} I noticed that momentum is not conserved. Well if momentum is not conserved then that means it is...
13. ### Series againand again

Sorry about the title everyone but ive posted numerous threads on series and I had to choose an apropriate title :tongue2: The problem asks to use the ratio test, and determine for which values of x the test is conclusive-either converging or diverging. Then check those cases where the test is...
14. ### Understanding series?

Understanding series????? The question in the book states Find the values of x for which the series converges, Find the sum of the series for those valuese of x this is the series \sum_{n=1}^{\infty}\frac{x^n}{3^n} first of all I dont even really understand what its saying, is it saying...
15. ### Easy professors

I was wondering if I should take easy professors for my math and physics classes? I am about to register for spring and I found an easy teacher for vector calculus. Im tired of having the hard profs..I mean I know regardless of how hard my teacher is, Im gonna work to my full potential in my...
16. ### Brain Fart

I dont know whats wrong with me...I have been studing for 6 hrs straight...and i noticed I have been making stupid mistakes...so can somone tell me whats up with my work...this is what I did. \sum_{n=2}^{\infty}\frac{1}{nln(n)} must show if it converges or diverges soooo this is what i did...
17. ### Methods for convergence divergence

I have \sum_{n=1}^\infty{\frac{1}{n^2+n+1}} and I need to show that it converges or diverges. I choose to do the comparison test making A_n=\sum_{n=1}^\infty{\frac{1}{n^2+n+1}} and B_n=\sum_{n=1}^{\infty}\frac{1}{n^2+n} so far so good? Okay well \lim_{n\rightarrow0}B_n=0 so does A_n...
18. ### Second rule of comparison in math series

I cant understand this \sum{A_n}\leq \sum{B_n} having said this if \sum{B_n} converges so does \sum{A_n}, okay that makes perfect sense but then the second rule of comparison is if \sum {A_n} diverges then so does \sum{B_n} diverges too...can anyone tell me how that makes sense? A...
19. ### Math for q-physics

I was wondering how much math you need to know to do quantum mechanics? Is multivariable calculus sufficient?
20. ### 1st and 3rd laws

I had a question about a particle with mass m=3.0kg if you take this mass and push it up against a wall how much force would you have to apply to keep it from falling if you had \mu_s = .7? where \eta is the normal force and P is the push force what I did was apply the first and 3rd...
21. ### Solve a radial acceleration problem?

I wanted to konw what is the least amount of knowns you need to solve a radial acceleration problem? My friend told me he was given a problem where a care was traveling over a bump and the only known he had was the speed of the care, no radious, no nothing. And the question was to solve for...
22. ### News What is the problem

It seems to me that before we got ourselvs into the war in Iraq the problem of "terrorism" was simple. What did the "terrorists" want..only 2 things. They wanted us to get our troops out of Saudi Arabia (wich is Islams holiest land..if im not mistaken) and to stop our unconditional support for...
23. ### Friction force physics problem

a stockroom worker pushes a box with mass 11.2kg on a horizontal surface with a constant speed of 3.50m\s^2 The coeficient of friction is (for surface of the ground and box) .20 A...what horizontal force must the worker apply to maintian the motion.. i got F_x=21.9N which is correct and then it...
24. ### Tension homework question

I am having trouble figuring this out. " Two blocks are connected by a uniform rope with a mass of 4.00kg. An upward force of 200N is applied. ...a)what is the \vec{a} of the system and what is the tension at the top of the rope. The \vec{a} of the system would have to be...
25. ### Ant crawls on a meter strick with acceleration

I have a question ..an ant crawls on a meter strick with acceleration a(t)=t-1/2t^2. After t seconds the ants intiial velocity is 2cm/s. The ants initial poistion is the 50cm mark. So ten \int_{a}^{b}f(t)dt and v(t)=1/2t^2-1/6t^3+c and because v(0)=2m/s the equation is...
26. ### Purpose of computing work

Can someone tell me what im doing wrong? "A glass is a cylinder, 15cm tall and with a radius of 3cm. It is filled 12.5cm high with water d=1000kg/m^3. A straw is placed in the glass, with the top of the straw 5cm above the top of the glass. How much work does it take to drink through the...
27. ### Can you allways use speed = distance /time relation

My question is when you know your velocity and the distance traveled....can you allways use speed =distance /time relation to find time..? Because it seems to only work on some occasion...i know this sounds like a stupid question but i just dont get it. Or does your velocity have to be conastant...
28. ### Cant see my mistake

I cant seem to get the correct answer but I keep getting very close the question is \int_{0}^{\pi/2}xcos(x)dx this is what I did u=x v=1/2(sin(2x))dx du=dx dv=cos(2x)dx and then i get...
29. ### Fundament Confusion

Hello page...im taking integral calculus and we are past integration of improper integrals. I know how to use the fundamental theorm but i dont get the first part... \frac{d}{dx}\int^x_af(t)dt=f(x) the book used it in an example....find the dirivative of g(x)=\int_0^1\sqrt{1+t^2}dt....the...
30. ### Integrating gravity(g)= -9.8m/s

correct me if im wrong.... By integrating gravity(g)= -9.8m/s....you get the motion equations with constant acceleration I didnt know how to set the limits of the integral...LATEX IS TUFF d\vec{a}=(-g)dt 1 \int_{\vec{V}_0}^{\vec{V}}dv=\int_{t_0}^{t_1}{-g}dt 2 \Delta{\vec{v}}=(-g)t...