# Search results

1. ### Combined Translational & Rotational System Transfer Function

Thanks for your response. Should this go in the advanced physics forum? This question is actually from a control systems class, but I posted it in the physics forums because I'm having a hard time understanding the physics behind this problem, especially the free body diagram. I was able to...
2. ### Combined Translational & Rotational System Transfer Function

Homework Statement I'm given the following diagram And asked to find the transfer function G(s) = \frac{X(s)}{T(s)} and seem to be having some difficulty doing so. Homework Equations The Attempt at a Solution Apparently this is free body diagram I seem to be having difficulty...
3. ### Interference of Light - Thin Film

Thanks for all of the help guys. It make since to me now. I clicked on all of the links, but was shocked by the link in #6 that went to a AP Physics B class website. I took that class four years ago and learned this material then, apparently I have forgotten all about it in such a small amount...
4. ### Interference of Light - Thin Film

This is interesting no one has ever explained this to me. How do I know when they invert and how do I know when they don't? Δ = Δ_{p} + Δ_{r} The inverted wave travels 2t as far since it travels through the thickness twice, so then why do we use 2nt as apposed to just 2t for thin film...
5. ### Interference of Light - Thin Film

My book doesn't mention this until Michelson interferometer. It doesn't explain why your supposed to use lambda/2. It appeared in my lecture in thin film interference. I can't seem to find though any explanation as to where it comes from. I also have searched the internet for some sort of...
6. ### Interference of Light - Thin Film

Homework Statement Plan plates of glass are in contact along one side and held apart by a wire 0.05 mm in diameter, parallel to the edge in contact and 20 cm distant. Using filtered green mercury light (λ = 546 nm), directed normally on the air film between plates, interference fringes are...
7. ### Doppler Effect of a laser

Wait hold on. What allows us to simply replace the wavelengths with the frequencies and just interchange them? I thought that the equation applied to wavelengths. Oh ok I know why lol.
8. ### Doppler Effect of a laser

Ya. I just read underneath that part and it says that when v << c Eq. (4-44) (the equation I posted in the first post for the Doppler Effect) is approximated by \frac{λ^{'}}{λ} = 1 - \frac{v}{c} Which I didn't realize. I remember reading it earlier but it left my mind because I would...
9. ### Doppler Effect of a laser

Homework Statement A laser emits a monchromic beam of wavelength λ, which is reflected normally from a plane mirror, receding at a speed v. What is the beat frequency between the incident and reflected light? Homework Equations The Attempt at a Solution The solutions starts off...
10. ### Laser Operation - Gain Media

I have just read the caption of the figure and now realize that v_{p}≈\frac{E_{3} - E_{0}}{h}. The only problem now is that I don't know E_{3} or E_{0}. Looks like I might be able to solve this. I was able to solve the problem. My only concern is that I didn't use the given wavelengths in the...
11. ### Laser Operation - Gain Media

I'm not sure if this question should be posted in the introductory physics section or the advanced physics section. Consider an amplifying medium, composed of homogeneous broadening four-level atoms as show in figure 26.5, page 557 of textbook. http://img689.imageshack.us/img689/6108/lt2f.png...
12. ### Superposition of Waves - Standing Waves

Oh wow. I can't believe I didn't see that thanks.
13. ### Superposition of Waves - Standing Waves

Homework Statement Consider a situation in which a wave is traveling in the negative x-direction encounters a barrier and is reflected. Assume an ideal situation in which none of the energy is lost on reflection nor absorbed by the transmitting medium. This permits us to write both waves with...

never mind
15. ### Dispersive power of glass

Homework Statement The dispersive power of glass is defined as the ratio \frac{n_{F} - n_{C}}{n_{D} - 1}, where C, D, and F refer to the Fraunhofer wavelengths, λ_{C} = 6563 \stackrel{o}{A}, λ_{D} = 5890 \stackrel{o}{A}, and λ_{F} = 4861 \stackrel{o}{A}. Find the approximate group velocity...
16. ### Wave Equations - Superposition

I start off with this E = E_{1} + E_{2} = \frac{5E_{0}}{(3x - 4t)^{2} + 2} - \frac{5E_{0}}{(3x + 4t - 6)^{2} + 2} = 0 I factor E = E_{1} + E_{2} = 5E_{0}(\frac{1}{(3x - 4t)^{2} + 2} - \frac{1}{(3x + 4t - 6)^{2} + 2} = 0 I expand 5E_{0}(\frac{1}{16t^{2} - 24tx + 9x^{2} + 2} - \frac{1}{16t^{2} +...
17. ### Wave Equations - Superposition

I thought that the \frac{1}{s} and \frac{1}{m} where units? So I removed them to make my expressions less messy. When I leave x and t in the expression and solve I get \frac{16t^{2} - 24tx + 48t + 9x^{2} - 36x + 38}{16t^{2} - 24tx + 9x^{2} + 2} = 1 I'm not sure how that really helps or how I'm...
18. ### Wave Equations - Superposition

So how would I go about solving the problem then?
19. ### Wave Equations - Superposition

Homework Statement Two plane waves are given by E_{1} = \frac{5E_{0}}{((3 \frac{1}{m})x - (4 \frac{1}{s})t)^{2} + 2} and E_{2} = -\frac{5E_{0}}{((3 \frac{1}{m})x + (4 \frac{1}{s})t)^{2} - 6} a) Describe the motion of the two waves. b) At what instant is their superposition everywhere...
20. ### Group Velocity of Waves in Gas Problem

I'm not really sure how because I don't have an equation for ω and am not really sure how it related to the problem. Is it rotational speed in this case or another variable? I don't see how rotational speed relates to k in this case and I believe is where I'm getting stuck.
21. ### Group Velocity of Waves in Gas Problem

Homework Statement The dielectric constant k of a gas is related to its index of refraction by the relation k = n^{2}. a. Show that the group velocity for waves traveling in the gas may be expressed in terms of the dielectric constant by \frac{c}{\sqrt{k}}(1 -...
22. ### Circuit Problem with diodes and resistors with sine wave input

Well when Vi is at it's peak positive voltage of 100 V the diode on the left is in the off state and acts like an open circuit. The diode on the right side is in the on state and allows current to flow though. The resistor branch on the right has 45.455 mA flowing through it and Vo = 100 V...
23. ### Circuit Problem with diodes and resistors with sine wave input

Homework Statement Sketch Vo for the network shown (see attachment) and determine the dc voltage available. Homework Equations The Attempt at a Solution Vi is a sine like wave with amplitude of 100 V and goes on for one period. When Vi is positive, the diode on the right goes...
24. ### Light and Magnetic Field

Homework Statement I'm not sure if this goes in introductory physics for not, but anyways... A light wave is traveling in glass of index 1.50. If the electric field amplitude of the wave is known to be 100 \frac{V}{m}, find (a) the amplitude of the magnetic field and (b) the average...
25. ### Electrical Circuit Question - Integrating Amplifier

Thank you for your help. I was able to solve the problem.
26. ### Electrical Circuit Question - Integrating Amplifier

So if I understand correctly you mean that Vout becomes zero?
27. ### Electrical Circuit Question - Integrating Amplifier

Homework Statement http://img801.imageshack.us/img801/4227/capturebsw.png [Broken] Homework Equations The Attempt at a Solution Alright I'm not really sure how to solve this problem. I have redrawn the circuit below without the operational amplifier. In ideal operation amplifiers...
28. ### Electric Circuit Question - RC Circuit

Well that makes since and I don't know why instead of using superposition I can't just use the fact that the net charge must be zero at the node. I checked that the voltage before capacitor one is 12 volts, the voltage before the second capacitor is 6 volts, the voltage before capacitor 3 is 0...
29. ### Electric Circuit Question - RC Circuit

They do absolutely nothing. So when I was trying to solve it using that the net charge must be zero. (2*10^(-9))(Vx-12)+(6*10^(-9))(Vx-6)+(4*10^(-9))(Vx-0)+(8*10^(-9))(Vx-2)=0 which solves out to be 3.8 however when I build in circuit labatory I get just about 5 volts even. I think I'm doing...
30. ### Electric Circuit Question - RC Circuit

I'm just looking for the steady state value of the voltage at that node.