# Search results

1. ### Small Engine Dyno

I am currently in the process of designing an engine dynamometer for a small engine. Maximum power of 1 KW @ 7000 RPM and a maximum torque of 1.6 Nm @ 5500 RPM. Here is my proposed method, but I have some concerns that I'll state below: Prony Brake Essentially a friction dyno, I would...
2. ### Modeling a mass-spring-damper system

Homework Statement Homework Equations The Attempt at a Solution This is one of our past homework assignments with the solution given to us. I'm trying to work my way through each part of this assignment but am getting stuck on a few aspects of the model. My approach: I first set up a...
3. ### Engineering Mechanical Engineer at a Nuclear Power Plant

Can anyone tell me who is a Mechanical Engineer and works in a Nuclear Power Plant, just what their daily duties include? How they like the work environment and such. I'm interested in knowing because as a student, my university has a Co-op program. Recently, I sent out my resume to FirstEnergy...
4. ### Archived Fluid Mechanics - Piezometric Head

Homework Statement Homework Equations Provided above The Attempt at a Solution Piezometric head is defined as the pressure head plus the elevation head, correct? But how does having a high piezometric head tell you about the fluid flow? Since the diameters are equal, the area's are...
5. ### Find the change in enthalpy

Homework Statement Homework Equations h_2 - h_1 = (u_2 + P_2v_2) - (u_1 + P_1v_1) The Attempt at a Solution I thought I had to look at the charts in the book for saturated liquid, then notice that the temperature is much higher at the given pressure than what was given in the problem...
6. ### Convergence/Divergence of an Integral

Determine whether the integral converges or diverges: \int_0^{\infty}(t^{-2}e^t) dt What would be the first step here in determining convergence or divergence?
7. ### Transformers - Find n1 and n2

Homework Statement [PLAIN]http://img192.imageshack.us/img192/8428/circuits.png [Broken] Homework Equations \frac{V_L}{V_s} = \frac{nR_L}{n^2 R_s + R_L} R_s = \frac{R_L}{n^2} P = \frac{V_L^2}{R_L} The Attempt at a Solution How should I go about solving this problem? Do I...
8. ### Undetermined Coefficients - Duplication Question

I'm having some problems recognizing duplication when using the undetermined coefficients method to solve homogeneous type differential equations. http://college.cengage.com/mathematics/larson/calculus_early/3e/shared/chapter15/clc7eap1504.pdf Example 2 on Page 1119, could someone explain...
9. ### 4th Order Variation of Parameters

Find the complementary solution of y^\left(4\right) + 2y'' + y = sint Homogeneous Form would be y^\left(4\right) + 2y'' + y = 0 r^4 + 2r^2 + r = 0 \rightarrow r(r^3 + 2r + 1) = 0 This is where I'm stuck. Once I find y_c(t) I should be able to finish the problem, but I'm having trouble at this...
10. ### Solve using Undetermined Coefficients

y''(t) - \frac{2}{t^2}y(t) = 3 - \frac{1}{t^2} In this problem I had to solve two ways: Variation of Parameters and Undetermined Coefficients. I solved it using Variation of Parameters and got the correct answer for the particular solution in the back of the book being y_p(t) = t^2ln|t| +...
11. ### Electric Circuits - Find the Equivalent Resistance (Dependent Source within circuit)

Homework Statement [PLAIN]http://img856.imageshack.us/img856/8508/circuit.png [Broken] Homework Equations Loop Analysis and Node Analysis The Attempt at a Solution The Question states I have to find the equivalent resistance within the circuit. But, since there is a dependent...
12. ### Apply Nodal Analysis to the Circuit

Homework Statement Apply nodal analysis to the circuit to find the power (released or absorbed?) by the 3-mA source. [PLAIN]http://img15.imageshack.us/img15/1546/circuity.png [Broken] Homework Equations Ohm's Law V = IR The Attempt at a Solution OK, so firstly I have to label...
13. ### Design a circuit to recharge a battery

Homework Statement Design a circuit to recharge a 1.2-V Ni-Cd battery from a car battery with a current of approximately 10 mA. Homework Equations The Attempt at a Solution I was looking in the back of the book on this one and it had a simple circuit devised with a 12-V battery...
14. ### Designing a voltage divider

Homework Statement Using a 100-kOhm potentiometer and suitable external resistances, design a voltage divider circuit such that varying the wiper from end to end varies the gain over the range: a) 0 to 0.75 V/V b) 0.2 V/V to 1 V/V c) 0.1 V/V to 0.9 V/V Homework Equations Not Sure...
15. ### Find the node voltages of the circuit

Homework Statement [PLAIN]http://img339.imageshack.us/img339/6089/electriccircuits221revi.png [Broken] Homework Equations i = v/R The Attempt at a Solution My attempt at the solution is all in the red in the diagram above. Apparently the book's answers are 1 V and 2 V and it...
16. ### Electrical Circuits - Find the power and Voltage

Homework Statement [PLAIN]http://img143.imageshack.us/img143/3746/electriccircuits.png [Broken] Homework Equations The Attempt at a Solution Can someone help me with part B of this? I understand that in part a it says the 5 A source is delivering 10 W of power, so that would in...
17. ### 3-D Statics Problem

Homework Statement [PLAIN]http://img846.imageshack.us/img846/6546/statics.png [Broken] Homework Equations Fy = F*cosθy Fh = F*sinθy Fx = Fh*cosφ = F*sinθy*cosφ Fz = Fh*sinφ = F*sinθy*sinφ The Attempt at a Solution I'm having a lot of trouble drawing vector AD in a free body diagram. I...
18. ### Relativity Problem

Homework Statement You point a laser flahlight to the Moon, producing a spot of light on the moons surface. At what minimum angular speed must you sweep the laser in order for the light spot to streak across the moons surface with speed v > c? Why cant you transmit information between...
19. ### Statics: Find the Tension

Homework Statement [PLAIN]http://img28.imageshack.us/img28/2106/241s.png [Broken] Homework Equations ΣF = ma The Attempt at a Solution I'm really confused here, is using ΣF = ma even possible to find the tension here? Or do I have to utilize some other method, like law of sines?
20. ### Electric Circuits Problem

Homework Statement [PLAIN]http://img535.imageshack.us/img535/7201/electriccircuits113.png [Broken] Homework Equations p = dW/dt; p = vi; W = Integral (p(t)) dt The Attempt at a Solution I think for the most part I got parts a and b correct. What I'm having significant trouble...
21. ### Michelson's Interferometer Problem

Homework Statement [PLAIN]http://img828.imageshack.us/img828/7386/physicsch3581.png [Broken] Homework Equations Not sure The Attempt at a Solution the indicies of refracton are inversly related to the speeds, that is n=c/v . You find the time to go distance L in one arm t=L/v...
22. ### Building a Laser - Brewster's Angle Problem

Homework Statement You are making a laser with light of wavelength 310 nanometers using a MgF2 window (which will transmit the UV). The mirrors will be external so each end of the 'pumping' gas discharge tube must be cut at Brewster's angle so that there is no reflection from the surface as...
23. ### Snell's Law with a Prism

Homework Statement [PLAIN]http://img854.imageshack.us/img854/6030/physicsch3364.png [Broken] Homework Equations n2θ2 = n1θ1 The Attempt at a Solution To be honest I'm lost from the get go, I'm having trouble with visualizing what part a exactly wants. Part B, I think is just the...
24. ### Thin-film interference Problem

Homework Statement [PLAIN]http://img135.imageshack.us/img135/6027/physicsch3569.png [Broken] Homework Equations 2L = (m + 0.5) (λ/n) for m = 0, 1, 2, ... (maxima - bright film in air) 2L = m(λ/n) for m = 0, 1, 2, ... (minima - dark film in air) The Attempt at a Solution Bright...
25. ### Polarization and intensity with three polarizing sheets

Homework Statement [PLAIN]http://img855.imageshack.us/img855/7899/physicsch3333.png [Broken] Homework Equations I = 0.5*I_0 I = I_0*cos^2(θ) The Attempt at a Solution I_1 = 0.5*I_0*(cos 50)^2 I_2 = I_1*(cos 70)^2 I_3 = I2*(cos 50)^2 This is my attempt at the problem. This...
26. ### Ohm's Law Problem

Homework Statement Homework Equations R = (Rou*A)/L V = R/i The Attempt at a Solution In this one I don't really understand how my answer to part a is wrong. My Work: L = 5.9 cm = 5.9E-2 m diameter = 8.4 mm = 8.4E-3 m ... radius = 4.2E-3 m ... A = pi*r^2 = pi(4.2E-3)^2 =...
27. ### Find the electric potential

Homework Statement Homework Equations V = (sigma)/(2*epsilon_0)*((z^2 + R^2)^(1/2) - z) The Attempt at a Solution This was my full equation to find the total electric potential: V = (sigma)/(2*epsilon_0)*((z^2 + R^2)^(1/2) - z) - (sigma)/(2*epsilon_0)*((z^2 + r^2)^(1/2) - z)...
28. ### Electric Field over an infinite sheet

Homework Statement Homework Equations E = σ/2ε0 (infinite sheet) E = σ/2ε0(1 - z/(z^2 + R^2)^1/2) (charged disk) The Attempt at a Solution Is this the correct method below? E = σ/2ε0 (infinite sheet) - [σ/2ε0(1 - z/(z^2 + R^2)^1/2)]
29. ### Electric Field for a line of charge

Homework Statement Homework Equations E = λ/2π*r*ε0 (Line of charge) The Attempt at a Solution E1 = E2 = 0 I can set each equation equal to each other and have 2π*ε0 cancel out on both sides. Leaving me with: λ1/r1 = λ2/r2. My problem now is that I'm not sure what to use for...
30. ### Electric Field from an Arc

Homework Statement Homework Equations E = k*Q/r^2 The Attempt at a Solution I tried to get the factor through integrating, but it was wrong.I ended up with (k*lambda*2)/R multiplied by the integral of cos(theta) dtheta. Limits were 10pi/21 and 0. I then divided by k*Q/r^2.