Dot Definition and 552 Threads

  1. L

    Applications of vector dot product in physics

    I have to present shortly five applications of vector dot product in physics, for example: W=F*s. I am not quite clear about vectors, so could someone advise me.
  2. T

    Vectors with appl of dot product

    I'm trying to solve this problem with different approaches. Link is here http://img138.imageshack.us/img138/2268/problem1eb1.th.png the answer is 0i + 0.0927j + 0.0232 k lb* Means DOT Method one: Find the force in scalar components. Then Take the cross product of two position vectors to get...
  3. T

    Work done on a force using dot product

    The question with all the info is: A force F = (6x i + 5y j) N acts on an object as it moves in the x direction from the origin to x = 5.04 m. Find the work (work = integral of F (dot product) dx done on the object by the force. I am confused as to what dx would be in this equation, and how...
  4. J

    Vector question: dot product in cylindrical coordinates

    Hello. To find the work of a force, I have to perform a dot product between the force and a infinitesimal displacement. If they are in cylindrical coordinates, I can't manage to make the dot product. Please, could you help me? Thank you.
  5. T

    How Can Vector C Be Expressed in Terms of A, B, and u?

    Hello, my problem is as follows: Given that A and B are known vectors, and A \cdot C=u is a known quantity, and A \times C=B Express C in terms of A,B, u, and the magnitude of A So far what i have done was use the definition of the dot product as AC cos \theta=u, and cross product as AC...
  6. W

    Dot products - why does the vector become scalar

    As Gokul43281 correctly pointed out to me, the dot product of two vectors is a scalar. I looked up this page to read about this. Thing is, I think conceptually. I could simply accept that this is so, but I don't "see" why it so. As my screen name implies, I must know why something is so...
  7. F

    Dot product of basis vectors in orthogonal coordinate systems

    I'm doing a series of questions right now that is basically dealing with the dot and cross products of the basis vectors for cartesian, cylindrical, and spherical coordinate systems. I am stuck on \hat R \cdot \hat r right now. I'll try to explain my work, and the problem I am running into...
  8. H

    Prove Rectangle: Dot Product Help

    -Use the dot product to prove that the quadrilateral with vertices A(-4,1) B(4,5) C(7,-1) and D(-1,-5) is a rectangle. I tried find AB dot BC = 0, but I'm not getting 0. So I'm stumped. Can someone help me out? =/
  9. G

    Understanding the Derivative of a Dot Product: A Question on the Product Rule

    I have come across something that seems a little strange to me. The derivative of a dot product is something similar to the product rule. I am having difficulties grasping this. Isn't the dot product of two vectors a scalar? And then I always thought of a scalar as a real number and the...
  10. T

    Izit possible fabricate the quantum dot by cvd?

    izit possible if i take nanoporous alumina or nanoporous silicon into the cvd. use the gallium powder n flow the ammonia gas... can it make a gaN quantum dot? any idea to fabricate quantum dot without mbe? i think there sure has a simple and cheap way to make it... any idea? tanx
  11. C

    How Does Clifford Algebra Apply to Quantum Physics?

    I registered the website http://www.CliffordAlgebra.com . My purpose is to have a website that gives a decent education in the practical uses of Clifford Algebra, as I am interested in their applications to physics. Is there any desire over here for a more mathematical introduction to the...
  12. W

    Cross & Dot Products in Physics: A Comprehensive Guide

    Can someone help me understand about the cross product and dot product? And how and where can I apply it in physics in solving problems.
  13. D

    Are Inner Products and Dot Products Fundamentally the Same?

    Is there any difference between an inner product and a dot product?
  14. B

    What Does 'Quantum Dot Exciton' Mean?

    Why do we talk about " quantum dot excitons" ? For me, excitons and quantum dots are two distincts objects For me, excitons (at least in a bulk) are a bound state of an electron and a hole, bound by the attractive coulomb potential, and their binding energy and wavefunctions are the one of a...
  15. H

    Can you help with Electron Dot Structures for these 6 compounds?

    I got another problem with my Chemistry Homework. I need to put the Electron Dot Structure for the following. 1) Lead Oxide 2) Potassium Sulphide 3) Sodium Nitride 4) Silver Oxide 5) Copper Chloride 6) Calcium Chloride Hope somone can help
  16. infraray

    Dot Product Calculator Quandry

    I'm going nuts here and I can't figure this out. I have two complex vectors: A=(1+i)x + (1)y +(i)z B=(4-i)x +(0)y + (2-2i)z If I do the dot product of these on my calculator I get 1 + 7i, however when I do this by hand I keep getting 7 +5i. What am I doing wrong? When figuring this out by...
  17. E

    Rules regarding the vector cross product and dot product

    hi, I'm currently doing a mechanics module at Uni. The thing is, I'm not very sure about rules regarding the vector cross product and dot product. For example, it says in my notes for angular momentum: "Introducing polar coordinates \mathbf{r} = r(cos \Phi \mathbf{i} + sin \Phi...
  18. A

    Name Geometric Shapes Based on Lewis Dot Drawings

    Give each group a shape name based on geometry. This one does not have to be "correct," but I want you to remember what the molecules look like for application later in the unit. H2O NH3 CH4 H2S CCl2F2 I've drawn both a Lewis dot drawing and a stereo projection for each but I still...
  19. L

    How to: Force, work & dot product

    A force in the xy plane is given by: F= - (b/r3) (x i^ + y j^) where b is a positive constant and r= sqrt(x2 + y2) a) Show that the maginitude of the force varies as the inverse of the square of the distance to the origin and that its direction is antiparallel (opposite) to the radius vector...
  20. B

    Differentiation and dot product

    Can someone help me with the following question. I've been having trouble with problems of this kind for a while now. Q. If the path u(t) (u is a vector) is differentiable at least three times, simplify: \frac{d}{{dt}}\left[ {\left( {u' \times u''} \right) \bullet \left( {u' - u}...
  21. M

    Dot product with 3 dimensions, confused on concept, easy question i think

    Hello everyone! I'm confused on what I'm suppose to do here, I think i might got it though but i need to make sure... Here is the problem and my work: http://show.imagehosting.us/show/764032/0/nouser_764/T0_-1_764032.jpg he let r(t) = f(t) i + g(t) j + h(t) k. So if i multiply this by...
  22. K

    How Does the Electron Dot Diagram for CN Look?

    how would the electron dot diargram for CN look? i am tired and stumped.
  23. M

    Dot product, i don't see what they want from me

    hello everyone, i understand the dot product and its properties but i don't get what they want! They say... The dot product of two vectors are perpendicular if a.b = 0. Then any vector in R^3 perpendicular to -5 -6 -3 note: that is a matrix above. can be written in the form...
  24. D

    Geometric Proof of Dot Product: |A dot B| ≤ |A||B|

    I am doing a assingment for my classical mechanics class that requires the proof of: The dot product of |A dot B| <= (less than or equeal to) |A| |B| . I did the algebraic proof fine but we are required to do a geometic proof as well. This leaves me with the question what is the geometic...
  25. U

    Dipole Dipole and Lewis Dot structes

    Why doesn't HOOH dipole dipole forces? I read that if a molecule has an Oxygen atom, it's likely to have dipole forces. This one only has Dispersion forces. Also, why does the Lewis structure of this molecule NOT look like this:
  26. M

    Showing dot product is commutative, please

    Hello everyone. I'm trying to show ab = ba. //communative property of dot product This is what I have, is it enough to show this? ab = (ax, ay, az) \dot (bx, by, bz) = axbx + ayby + azbz; a\dotb = (axi + ayj) (bxi + byj); //note: i and j are unit vectors = axbx(i)(i) + ayby(j)(j) +...
  27. M

    Conceptual explanation of Dot Product

    I'm a peer leader for a general physics lab and someone asked me to explain what the Dot Product meant conceptually. I told him it was the projection of A onto B multiplied by the magnitude of B. He looked even more confused after that; my questions are: a) Did I explain it correctly...
  28. M

    Show the commutative property with dot product

    Hello everyone, does anyone know the proof of the dot products communative property (a)(b) = (b)(a) or any websites that show the dot products communative property? or other properties? Thanks! The book only shows the distributed property.
  29. D

    Understanding Dot Product: Identity and Unit Vectors

    What is the dot product of a unit vector (e) with a non-unit vector (A)? Is this some sort of identity? Thanks, don_anon25
  30. D

    Questions concerning cross products, dot products, and polar coordinates

    Question answered! Thanks!
  31. S

    Learning vectors: the dot product of vectors

    Well, I've been attempting to learn dot products of vectors and in doing so have come upon some questions. NOTE: a, b, and c are to be regarded as vectors Please regard '*' as the dot for multiplication, too. Question 1: a * b * c When I see this, I am unaware how to approach it...
  32. C

    Mystery of Jupiter's Red Dot: Uncovering the Cause

    why does the red dot on Jupiter i think its like a storm or something or a hurricane but does anybody know why it does not stop? and the cause of it ? thak u craig
  33. J

    Simplifying Dot Product Equations with Vectors - Need Help!

    i need help with the following: note that the big dots represents the dot product 1. suppose that a \bullet b = c \bullet b for all vectors \overrightarrow{b} . show that \overrightarrow{a} = \overrightarrow{c} . i suppose i can't simply divide out the b, right? anyway, i tried...
  34. A

    How do you draw electron dot diagrams for pentyne?

    I am having a difficult time understanding how to do dot diagrams, more specific for "pentyne"
  35. P

    Keeping only one digit after the dot.

    Hello, Is there a mathematical way to get rid of all the digits after the dot except one? 10.292288.. how do i just make it 10.2?
  36. M

    What Are Some Dot Product Questions in Geometry and Discrete Class?

    I have some questions from my geometry and discrete class.. #1 Given a and b unit vectors, a) if the angle between them in 60 degrees, calculate (6a+b)●(a-2b) b) if |a+b|= root(3), determine (2a-5b)●(b+3a) #2 The vectors a=3i-4i-k and b=2i +3j-6k are the daignols of a parallelogram...
  37. P

    Can you help me draw multiple Lewis dot structures for ClO4-?

    I'm asked to draw 5 possible lewis dot structures for this ion. But I can only think of one. which I 've attached here. I'm supposed to draw them and determine which is the most favorable. I know I can do that by calculating hte formal charges, but first I need to draw these structures. Any...
  38. A

    Quantum Dot Problem (Griffiths 7.20)

    Hello, Damn Griffiths 3-star problems... The setup for the potential is a 2D cross basically, so there's a column of zero potential 2a wide (straddling the y-axis) going to +/- infinity, and there's the same thing on the x-axis, so they cross over the origin. Everywhere else the...
  39. RadiationX

    Understanding Vector Dot Product: Solving for a, b, and c in a Right Triangle

    i have three vectors: a=4,b=3,c=5 that form a right triangle. vector a is in the positive x direction, vector b is in the positive y direction starting at the tip of a. vector c is the hypotenuse of the triangle with tip at the origin. (see attaced picture .doc file) the questions are...
  40. S

    Understand Lewis Dot Structures: Cl F & Triple Bonds

    What would the Lewis structure look like for Cl F? Would it look like this: http://img53.exs.cx/my.php?loc=img53&image=dot8pn.png How do you know when there is a triple bond? ~Thanks
  41. Mk

    Learning to Pronounce Dot Cue (\dot{Q})

    How do you say... \dot{Q} ...Dot cue?
  42. M

    What Is the Unit Vector Perpendicular to Both 4i - 3j + k and the z-Axis?

    I'm sorry if this is placed under the wrong section of the forum. But i really need help with a problem. Well, here it is; Find a unit vector that is parallel to the xy-plane and perpendicular to the vector 4i - 3j + k *note* there is a ^ above the ijk.
  43. G

    A disk 8.0 cm in diameter is initially at rest. A small dot is painted

    A disk 8.0 cm in diameter is initially at rest. A small dot is painted on the edge of the disk. The disk accelerates at 600rad/s^2 for .5s, then coasts at a steady angular velocity for another .5s. What is the speed of the dot at t = 1 s? Through how many revolutions has it turned? I...
  44. B

    Why is Perpendicularity in 2D and 3D Important?

    Let n = (a,b,c) v = (x,y,z) Whatever the dot product of these vectors equal to, let's call d, the vector n is perpendicular to v. Again, I cannot stay calm and ask WHY? If we call n = (a,b); v= (x,y) ==> ax+by= d and the slope of this line is -a/b whereas the slope of the vector n is...
  45. C

    Calculating the Dot Product: A*B

    I need some major help with some dot products. I was curious if when getting the dot product, you add the angles of each one to each other. I'll give the problem: theta=(/) Find A*B(dot product) A=8.6i+5j B=9.7i+2.6j So i used the formula my teacher gave me to find the angle, theta...
  46. F

    How Does Carl Sagan's Pale Blue Dot Alter Our Perspective of Earth?

    http://www.cs.princeton.edu/~bourgui/misc/pix/pale_blue_dot.jpg Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering...
  47. D

    Understanding the Units of the Dot Product

    Hi, I got a simple question, "dot product" have units? I mean, if A=(Ax+Ay+Az)N and B=(Bx+By+Bz)(cm/s) , the units of A.B will be N.(cm/s) Thanks, Cali
  48. J

    Electron Dot Diagram and Structural Formulas

    Hello, I was hoping someone here might be able to explain to me how to determine electron dot diagrams and structural formulas of diatomic/polyatomic elements and compounds. For example... Nitrogen Tri-iodide ( NI3 ) I know the basics of electron dot structures, but when the atoms start...
  49. P

    Find p Given a.b = 4, a=[6,3,-2], b=[-2,p,-4]

    The angle between vectors a and b is cos^-1(4/21). Find p if a = [6,3,-2] and b = [-2, p, -4] I did: cos x= 4/21 = a.b/|a||b| The result comes out to be p=8/3 but it only satisfies that a dot b is 4 and not |a||b| = 21...What am I doing wrong?
  50. Juntao

    Help with simple dot product proof

    Here's what I got to prove where '.' is dot. A.B=A.C Then B=C True or false? If true, prove it in general terms, if false, provide a counter-example. Ok, I just need some body to comment on my little proof here, and any guidelines to make it more thorough or whatnot. I know that the dot...
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