# Search results

1. ### Small Engine Dyno

So essentially what I would have is the following: An engine with a centrifugal clutch mounted on the flywheel Machine a shaft of 3/8" diameter to mount inside the clutch housing Along this shaft, I would have a set of ball bearings to support the shaft The brake rotor would be mounted in...
2. ### Small Engine Dyno

Sorry for the double post, but I think I understand what you are saying now with the torque arm mounted on the bearing itself. http://www.smaltd.com/FreeWheels.htm You are referring to this right? Where the bearing housing is essentially the load absorber and the reaction arm would rest...
3. ### Small Engine Dyno

Its a single cylinder, 4-stroke internal combustion engine with a pull start. The test won't be ran very long, I would expect 5 minutes maximum if that. The goal of the friction brake dyno would be to start the engine, open the throttle all the way, and apply the brake until the desired RPM is...
4. ### Small Engine Dyno

I've actually considered three other dynamomters (such as what you have listed). In terms of simplicity and efficiency for a low horsepower engine like the one I described in the OP, what would you suggest be the dynamometer? I only know of 4 possible choices: Inertia Dyno (Utilizing a flywheel...
5. ### 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...
6. ### Modeling a mass-spring-damper system

Ah now that makes sense. I should have thought of it like that. By the way, when dealing with the spring k2 in these problems, is the reason why you have to take the position x2 into account when looking at mass 1 because the masses are connected via that spring? I guess what I'm saying is at...
7. ### Modeling a mass-spring-damper system

Hmmm but how I understand the forces on springs in part b) is that the force from spring 1 acting on the wall is towards the right. Thus equal and opposite on mass 1 makes that spring force to the left. That's what I thought you do for spring 3 in part b) as well. You look at the force spring 3...
8. ### 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...
9. ### Engineering Mechanical Engineer at a Nuclear Power Plant

That sounds pretty interesting and like you said would be a great learning experience. My other question is, how much of the time would you be suited up to protect against radiation while working in a nuclear power plant? The job description said that I'd be in an office 40% of the time and in...
10. ### 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...
11. ### 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...
12. ### 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...
13. ### Convergence/Divergence of an Integral

So if both have no limit and diverge, then by comparison test the whole integrand diverges? Edit: Just noticed you have the limits a little different. How did you determine the limits to be those when evaluating them separately? I get \int_0^1 t^{-2} dt = -1 And \int_1^{\infty} e^t dt =...
14. ### 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?
15. ### Transformers - Find n1 and n2

Yeah I was talking about part a) Apparently some others were able to get the 10,000 W power for part a that was int he back of the book though I couldn't really follow what they did.
16. ### Transformers - Find n1 and n2

In part a) I found n2 to be 10, but how do I find the max power now? I used the equation I posted in the OP to find the load voltage then used P=\frac{V_L^2}{R_L} but I get 115.2 W as power when the book has 10,000 W roughly. Perhaps it's because I use the wrong value for R_s. I used 20 Ohms...
17. ### Undetermined Coefficients - Duplication Question

Yeah I understand how its duplicated from what you said but I had thought that dupilcates only arise from looking at the terms that are present in y_c(t) and g(t) so that's why I'm confused because you are telling me to look at a term in the particular solution, y_p(t), and see if it has...
18. ### 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...
19. ### Undetermined Coefficients - Duplication Question

Ok that makes it a little clearer now. I used the above O.D.E. because it was on my homework and I was wondering which Particular Solution to go with. I can obviously see the duplication of e^t. But, what I'm having trouble understanding is what is duplicated to cause the polynomial At + B to be...
20. ### Undetermined Coefficients - Duplication Question

I'm having trouble following what you just said there but for a problem like this: y'''(t) - 3y''(t) + 2y'(t) = t + e^t y_c(t) = C_1 + C_2 e^{2t} + C_3 e^t Initial guess would be: y_p(t) = At + B + Ce^t But since e^t is present in the differential equation and the complimentary solution...
21. ### Undetermined Coefficients - Duplication Question

The way I look at it is like so: g(t) = x + 2e^x and y_c(x) = C_1 + C_2 e^x So that would mean duplication of the term e^x So to compensate for that, multiply your particular solution by the variable x. But my question is this: Do I multiply every term in the particular solution by x, or just...
22. ### 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...
23. ### 4th Order Variation of Parameters

Hmm, what exactly do you mean by those 2 equations?
24. ### 4th Order Variation of Parameters

After taking the particular solution to be: y_p(t) = U_1 (t)cost + U_2 (t)sint + U_3 (t)tcost + U_4 (t)tsint I then take the 4 derivatives and I ended up with the following 4 Equations (1st 3 are from the conditions that the U(t) derivatives add up to 0 while the last equation is derived...
25. ### 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...
26. ### Solve using Undetermined Coefficients

Yeah it does, I think I just misheard the teacher in him saying use undetermined coefficients when I think he meant use 2 methods of variation of parameters to get the particular solution. At least I hope he said that as that's what I did.
27. ### 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| +...
28. ### Electric Circuits - Find the Equivalent Resistance (Dependent Source within circuit)

My equations are: 30i - 30i3 = V 45i1 - 60i2 + 15i3 = 0 -30i1 + 60i2 - 15i3 = 0 -15i1 - 15i2 + 60i3 - 30i = 0 I can add equations 2 and 3 right away to get 15i1 = 0, so i1 = 0. But from then on I'm stuck, no matter what I try I can't seem to solve for another current.
29. ### Electric Circuits - Find the Equivalent Resistance (Dependent Source within circuit)

I'm almost completely lost at the moment after writing those equations down I can't seem to solve any at all. And I get a current for i1 = 0 Amps. Is that even possible? Is node analysis the easier approach here rather than working with 4 equations in loop analysis?
30. ### Electric Circuits - Find the Equivalent Resistance (Dependent Source within circuit)

Ok, the overall purpose here is to get the test current, i, in terms of the test voltage, V, so that I'll end up with a ratio for the equivalent Resistance in the circuit right?