# Search results

1. ### Identifying an element from Emission Spectrum

I cant really find any wavelengths to compare my calculated wavelengths to, just pictures of spectra, you cant make a positive id on that. e.g. I have a blue/violet 1st order to the right of center, wave length=348.99, and to the left of center=523.359. Looking at this...
2. ### Identifying an element from Emission Spectrum

Using data collected from a spectrometer, with a diffraction grating of 100 lines/mm, I have collected a set of data. From this I have calculated wavelengths for the 1st and 2nd order lines of the three brightest visible colors, which were Blue/Violet, Green, and Orange. To complete my lab...
3. ### Isoceles triangle in absolute geometry

Im working to prove that an interior point on a chord is also interior to the circle containing the chord. Ive got the entire proof almost finished and laid out, however im stuck on one part. My proof would be complete if I could show this: Given an isoceles triangle, in absolute geometry...
4. ### Radiated power, what does this even mean?

Honestly, Im not even sure exactly what radiated power means. Why is the 18.4mW not the radiated power of the light bulb? I thought electrical energy was essentially work, which is a product of power and time, so how could radiated power be anything except 18.4mW? Are they referring to...
5. ### Electric field lines

I know that the electric field lines between two oppositely charged points are symmetric, but I cant seem tof ind any refrence as to when this symmetry breaks down. I want to say that electric field lines do not maintain symmetry if the two charges are not equal but opposite, e.g. a -4 and +4...
6. ### Coaxial pair of infinitely long charged solid conductors

A) By definition linear charge density is Q/L. So for the inner conductor with 2λ I want to say it is 2Q/infinity but this cannot be right. Im sure using Guass's law produces a correct answer but I cannot see anyway to relate it to λ or length of the conductors for that matter B) For...
7. ### Capacitors connected in series.

Well you would have \frac{1}{C_{eq}}=\frac{1}{C_1}+\frac{1}{C_2} and \frac{1}{C_{eq}}=\frac{1}{C_1}+\frac{1}{C_3} and finally \frac{1}{C_{eq}}=\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_3} but how could you find the final charge without using a voltage?
8. ### Capacitors connected in series.

Ive tried so many different ways using the formula for series capacitors and Q=CV and Ive had no luck solving this problem. There must be some rule (or trick) Im missing involving combing C12 and C13 that im completely missing. Can anyone offer any insight into solving this problem?
9. ### Equivalent Impedence problem

Nevermind, I feel dumb now. I completly missed that j^2=-1
10. ### Equivalent Impedence problem

Given this problem and its solution: http://img230.imageshack.us/img230/9239/quest13lf.gif [Broken] I think the given solution is wrong. The equivalent impedence is R + jwL || 1/jwC, right? When I work out jwL || 1/jwC, I get ((jwL) * (1/jwC))/ (jwL + 1/jwC) = jwL / (j(w^2)CL + 1)...
11. ### Confusion regarding sin and cos

Generally Im confused about the use of sin and cos in physics problems. http://img188.imageshack.us/img188/3162/eg2gu.gif [Broken] The torque about the beam's attachment to the wall is: T * 8 * sin(53) Where T is the tension of the wire. Why is sin the choice and not cos...
12. ### Wave length of a transverse wave

Actually I just figured it out, thanks for the help!
13. ### Wave length of a transverse wave

Thanks, after that it was easy to solve. Iam still however lost on the first problem. So is it .83333 of a cycle out of phase, but Im still unsure as how to relate this to wavelength?
14. ### Wave length of a transverse wave

For #2, here is the full question: http://img137.imageshack.us/img137/8669/q229ni.gif [Broken] As for the first problem, their cycles are out of phase (5pi/3)/2pi = .83333, right? so if the points are 30cm apart, the wavelength is .8333 *30cm?
15. ### Wave length of a transverse wave

1) A transverse wave of frequency 25 Hz propa- gates down a string. Two points 30 cm apart are out of phase by (5*pi)/3 What is the wave length of the wave? An- swer in units of cm. Im kinda lost here, Im unsure how wave length will relate to the given info. Im sure the phase is part of...
16. ### Diodes confuse me

Thanks, it makes much more sense now. Just testing latex below here: theta=(s&pi;x)/&lambda;
17. ### Diodes confuse me

Yeah, .7v for D2 and .6v for D3. .7V for D1 also
18. ### Diodes confuse me

Im just working from the solution: http://img251.imageshack.us/img251/7074/answer6vb.gif [Broken] Even with the solution it makes little sense to me.
19. ### Diodes confuse me

Usually I can pick up most concepts pretty quickly, but EE just makes me feel dumb. Ive managed to grasp most concepts we have covered this semester, except one, diodes. I really dont understand how to determine forward or reverse bias. For example...
20. ### Confused on these problems

First, For a 3kg object, displacement is given by 6i+3j-4k with a constant force F=2N i + -1N J + 7N k. Ive found the total work, but the next question is ' Find the component of F in the direction of this displacement. Answer in units of N. ' Im really confused as to what is even...
21. ### || meaning

How would you compute the following, 9||2 Ive never seen this previously and i cant consistently match answers the book has for the various listings.
22. ### Archimedes principle and floating slab

ugh, nothing im doing is coming out right for this. for p1 and p2 im putting in h times g times 1000, filling in ½qv1 with 1/2 times 1000 times v1, and qgh with 1000 times 9,8 times height on tank. this is just not coming out right at all
23. ### Archimedes principle and floating slab

P1 + qgh1 + ½qv1 = P2 + qgh2 + 1/2qv2 im just confused on how to use it relating to this problem. p1 and p2 are the initial pressures on the holes, i think, so p1 = 1000 times 9.8 times 34 and p2= 1000 times 9.8 times 60 but then you plug these in and solve for h, correct, where h would...
24. ### Archimedes principle and floating slab

ah, ive figured it out, area = Mass / Thickness * (density of water - density of slab) im still pretty lost on the second problem.
25. ### Archimedes principle and floating slab

A styrofoam slab has a thickness of 12.6 cm and a density of 470 kg/m 3 . What is the area of the slab if it floats just awash (top of slab is even with the water surface) in fresh water when a 65.7 kg swimmer is aboard? Answer in units of m 2 . im trying to use pressure=density of...
26. ### Oscillations homework help

My instructor said the problem is solvable, but yeah, all we get is the length of the string and g.
27. ### Oscillations homework help

A meter stick, suspended at one end by a 0.502m long light string, is set into oscillation. Determine the period of oscillation in seconds. At first I thought this would be a rather simple problem, so I did T=2pi*sqrt(L/g) but apparently this is very wrong. Then I tried w=sqrt(g/l)...
28. ### Simple Harmonic motion problems

http://sweb.uky.edu/~lsadam0/problem2.JPG [Broken] Im kinda lost on this problem. Shouldnt the Y motion be described as A*sin(wt)? In there equation we are considering when x=0, so the kx term is removed, but where is this third term coming from, and then should Y motion just be...
29. ### Combination of Linear and Angular momentum

Ah, thank you very much for the help.
30. ### Combination of Linear and Angular momentum

A solid cylinder of mass M = 42 kg, radius R = 0.14 m and uniform density is pivoted on a frictional axle coaxial with its symmetry axis. A particle of mass m = 4.2 kg and initial velocity v0 = 17 m/s (perpendicular to the cylinder's axis) flies too close to the cylinder's edge, collides with...