# Search results

Ltkach2015
2. ### A Cross Product Matrix

I am not following. I should have said: assuming that the Levi Civita 3x3x3 matrix would have to remain the same for orthogonal curvilinear coordinates. That's my own thought as I knew I had to somehow generate the same velocity vector. And I think the article confirms my thinking; I quoted it...
3. ### A Cross Product Matrix

If given a position vector defined for a orthogonal curvilinear coordinate system HOW would the matrices that make up the Levi Civita 3x3x3 matrix remain the same? "Levi Civita 3x3x3 is said to be independent of any coordinate system or metric...
4. ### A Theory of Surfaces and Theory of Curves Relationship

Oh ok! So the sphere's gradient vector would point in the same direction as the circle's negative normal vector?
5. ### A Theory of Surfaces and Theory of Curves Relationship

Ok Why doesn't the normal to space curve contained on a surface not point in the same direction as that surfaces normal vector (gradient)?
6. ### A Theory of Surfaces and Theory of Curves Relationship

Hello I am interested in the Frenet-Serret Formulas (theory of curves?) relationship to theory of surfaces. 1) Can one arrive to the Frenet-Serret Formulas starting from the theory of surfaces? Any advice on where to begin? 2) For a surface that contain a space curve: if the unit tangent...
7. ### Alternative Methods vs Iterative Design — Control Theory

QUESTION (2/2) 1) What are some alternatives to iterative design in control theory? 2) I have a certain plant transfer function PTF(s) that is higher order than two and non-unity numerator. I want certain characteristics such as a certain damping ratio (zeta). So I want approximate it as...
8. ### Why Time Response Characteristics Derived from Zero State Equation

QUESTION: 1) Why are Time Response Characteristic's Expressions derived from only from Zero State Equations? NOTE: Nise Control Systems Engineering 6ed uses step inputs to derive Time Response Characteristics for 1st and 2nd order ordinary differential equations...
9. ### Zero Homogenous Solutions with transient Particular Solutions- Physically Possible? & More Questions

That is an error on my part. Correction: dy/dt + y = exp(-t) Zero-Initial Condition: y(0) = 0
10. ### Zero Homogenous Solutions with transient Particular Solutions- Physically Possible? & More Questions

ASSUMPTIONS: BIBO/stable systems NOTE: zero here does not mean the roots of the denominator in a transfer function TRUE/FALSE -Please provide feedback- some answers are based on ODE example listed below 1/True) The Homogenous Solution is either zero or transient.; i.e. it can never be steady...
11. ### Homogenous Solution Represents the Transient Response Right?

So, I was beginning to build a new and deeper understanding when I noticed that Particular Solutions can also be transient: Thus in that scenario, I believe, the Particular Solutions can, jointly, represent the Transient Response. And as expected there isn't a Steady State Response because the...
12. ### Homogenous Solution Represents the Transient Response Right?

Ok. Yes it is interesting. Thank you for the reply.
13. ### Homogenous Solution Represents the Transient Response Right?

CONCEPTUAL QUESTIONS: -Does the Homogenous Solution represent the Transient Response? Let me specify. For a N-DOF spring, mass, and damper mechanical system: -Does the Homogenous Solution represent the Transient Response for given mechanical system? MY ANSWER: Yes. ASSUMPTIONS: -only...
14. ### Dartmouth Extended Laplace Tables -- Not general enough? item26.a

Yes I agree the dimensions do look off
15. ### Dartmouth Extended Laplace Tables -- Not general enough? item26.a

Homework Statement [/B] http://www.dartmouth.edu/~sullivan/22files/New Laplace Transform Table.pdf (see item 26a) homogenous solution to underdamped in amplitude phase form: (see attached image) 2. Relevant info - non zero initial conditions: x(t=0) = xo AND dx/dt(t=0) = vo - unforced...
16. ### Steady Flow-Does That Mean ALL Properties of Flow are Steady?

QUESTION: In general: when a flow is considered steady does that mean all properties of the flow are steady? Or: can a flow have steady and unsteady properties?
17. ### Dynamics Problem: Not Understanding the Acceleration Term

I think you are totally right about it being on a horizontal plane. This take care of the solution. Wow. Thanks. I don't know what you mean about the directions, I believe I did show them.
18. ### Dynamics Problem: Not Understanding the Acceleration Term

Ok I would agree with you too, however, the problem forces me to do one of two things to get the same result: 1) ignore the weight term. I think some call it the dynamic case. or 2) the weight term is in fact apart of the total acceleration. Answer: Tab = Tdc = sqrt(2)*m*a
19. ### Dynamics Problem: Not Understanding the Acceleration Term

Homework Statement [/B] If particles at B and C of equal mass m are connected by strings to each and to points A and D as shown, all points remaining in the same horizontal plane. If points A and D move with the same acceleration a along parallel paths, solve for the tensile force in each of...
20. ### Projectile Motion on Inclined Surface Question

Hey TSny! Thank you it was a sign error! xi = -61.07 yi = -45.80 Range = sqrt[ (-61.07)^2 + (-45.80)^2 ] = sqrt(5827.17) = 76.33. close enough Thank you both for all your help. I was really confused.
21. ### Projectile Motion on Inclined Surface Question

Hi TSny, thanks for the quick reply. - the 'd' in the cosd does denote that the argument is in degrees (from matlab, dunno why I included it here) - the 'i' does mean intersection. apologies. - I will look into the sign error, hopefully that fixes it.
22. ### Projectile Motion on Inclined Surface Question

Hi mfb, thank you for the quick response. - Oh! Yes my my coordinate system is a right handed one: x positive right, y positive up - Unfortunately, my final answer is different than the solution. ANS: Range = 76.5 meters Range = sqrt( xi^2 + yi^2) = sqrt( 17.126^2 + 12.8449^2) = 21.4 meters...
23. ### Projectile Motion on Inclined Surface Question

Homework Statement Water is sprayed at an angle of 90° from the slope at 20m/s. Determine the range R. PLEASE SEE ATTACHMENT Homework Equations [/B] Kinematic Equations: acceleration: A = 0i +g(-j) + 0k; velocity: dV/dt = A; position: dR/dt = V; Origin set at the point...
24. ### Proof of Pascal's Law

Hello LFS, were you able to figure this out? I would love to know!
25. ### Resolved Shear Stress Compared w/ Shear Stress-Contradictioni

Hi I have reposted this on the homework help forums; I have adjusted the post to fit the template requirements. @: https://www.physicsforums.com/threads/resolved-shear-stress-vs-general-shear-stress-contradiction.813219/
26. ### Resolved Shear Stress VS General Shear Stress -Contradiction?

TERMS: Slip Plane: is the plane that has the densest atomic packing—that is, has the greatest planar density. Slip Direction: corresponds to the direction in this plane that is most closely packed with atoms—that is, has the highest linear density. NOMENCLATURE: θ = angle of the slip plane as...
27. ### Resolved Shear Stress Compared w/ Shear Stress-Contradictioni

TERMS: Slip Plane: is the plane that has the densest atomic packing—that is, has the greatest planar density. Slip Direction: corresponds to the direction in this plane that is most closely packed with atoms—that is, has the highest linear density. TEXTBOOK: Materials Science and Engineering...
28. ### Thermal Ckt Parallel Configuration & 1-D HeatFlow Contradictory?

Wow that makes a lot of sense! Though I still have some questions and responses to your answers. Answer 1&2: dT/dy = 0; no temperature difference between top and bottom! It's the temperature difference that drives the heat flow. Answer 3: Although the heat can still move in that additional...
29. ### Thermal Ckt Parallel Configuration & 1-D HeatFlow Contradictory?

1. My Conceptual Questions (5) is at 3. CONSIDER: Case 1: two dissimilar slabs of material (say slab 1 and slab 2) connected in series (bonded at their interface). There is a temperature difference: T1 @ slab1 and T2 @ slab2. Case 2: two dissimilar slabs of material bonded together, i.e...
30. ### Law of Mass Action vs The Reaction Rate Law

yes but can you prove it?