Concept Definition and 1000 Threads

  1. H

    Is the Limit of the Integral of a Function Equal to its Maximum Value?

    I am trying to prove that the Limit as p approaches infinity of {integral from 0 to 1[|f(t)|^p dt]}^(1/p) is in fact equal to the max of |f(x)| between [0,1]. Any suggestions I am sure I need to set the limit to less than or equal to and greater than or equal to the max but i don't quite...
  2. J

    Which Focal Length is Longer for Different Light Colors?

    Homework Statement 1. A converging lens is used to focus parallel beams of red light and then later used to focus parallel beams of green light. Which focal length is longer? Explain 2. A photographer moves closer to his subject & then refocuses the camera. Is the camera lens now closer...
  3. F

    What is the second mixed partial derivative of df/dx= 3-3(x^2)?

    Homework Statement Given the partial derivative df/dx= 3-3(x^2) what is d^2f/dydx? I'm not sure if the answer would be 0, since x is held constant, or if it would remain 3-3(x^2) (since df/dx is a function of x now?)
  4. C

    Concept based light and optics ?

    Homework Statement When a gas is heated, it emits red and green light. What is its color when it is cool? What % of light is reflected from a normal window? (answer choices 0, 20, 50 and 100) Homework Equations ? The Attempt at a Solution For the first question, I can't think...
  5. L

    Concept related Electrical circuit question

    Homework Statement im supposed to draw the circuit for a simple house In a household electrical circuit, there's 3 wires, the live one, the nueteral one, and the grounding one. I'v drawn it out as if it were a DC circuit, then replaced the wires with appropriate live, and nueteral wires, but...
  6. M

    Radio Contolled Helicopters Concept

    Radio Contolled Helicopters Concept! Hi guys does anybody know concepts behind the Fixed pitch Radio heli principle Thnx a lot in advance
  7. C

    Exploring the Relationship Between Capacitor Changes and Energy Requirements

    Homework Statement It's not a typical question but is a challenging question from my sir, That's consider 2 cases: 1- A capacitor connected with a d.c power supply 2- A capacitor (originally charged) with two ends open. These two cases undergo two changes,1- increase in the plate-to-plate...
  8. J

    2 concept questions on magnetism.

    Homework Statement http://img231.imageshack.us/img231/5296/physicspd2.jpg Homework Equations none really. The Attempt at a Solution 1. I think that the two outside magnets would attach to the middle one and their eventual velocities and accelerations would equal 0 but that...
  9. K

    Concept Question about Resonance and Oscillations

    This may sound like a strange question... I was walking away from my physics class today and I wondered if resonant vibrations were the reason my shoelaces become untied. I noticed that when I walk faster, and produce what I believe are more forced oscillations, they become untied more...
  10. S

    Chemistry Basic Mole Concept Questions, Grade 11 Chem

    Hey guys, I'm back, finished my term in physics with a 96% final grade, thanks to all you guys. So i thought id try you guys before i went to find a chemistry help forum. I get the Mole Concept, kinda, here's an example question (i got an answer, not sure if its right, we don't get a "back...
  11. Y

    Can a flying pig float in water like a conical pendulum?

    I have a question about the flying pig. A flying pig is just a toy pig with wings that is hung from the ceiling with a string. When you turn it on, it flies in a circle and shows concepts of conical pendulum. But it only flies in one direction. If you push the pigs in the opposite direction...
  12. A

    Exploring the Concept of Batteries | 65 Chars

    Could someone explain the concept of a battery I've looked it up in my textbook and wikipedia, but it doesn't really help Here is what I think I understand 1. Charges (electrons) are made in the cell by chemical reactions 2. They complete the circuit by leaving one of the terminals and...
  13. C

    Airgulper Concept: Injecting Air into a Tank - Darin Selby

    Please give some feedback on my latest drawing concept of 'injecting air into a tank instead of compressing it'. Thanks. http://darinselby.1hwy.com/airgulper.html
  14. G

    Unraveling the Concept of Relativity: Understanding Light and Time

    Over time, I've realized there are certain limits to how far the human imagination can go. Even for simple things, it seems that we can not imagine much further than what experience allows...anyways: How does this light and time thing work? How is it that time slows down as we go faster?? It...
  15. J

    Quick Electric Potential Concept Question

    Homework Statement Explain why the potential energy between a positive charge and a negative charge is <0 Homework Equations The Attempt at a Solution I honestly don't know, I've tried reading the text about electric potential and I just can't find anything on the subject.
  16. D

    How Are Forces Equal and Opposite in a Moving System?

    I am what is called an LA (Learning Assistant) for an introductory physics class and I'm a freshman. One problem in which I have in convincing the students is how forces are equal and opposite. For instance: A large truck breaks down out on the road and receives a push back into the town by a...
  17. R

    Virtual Short Concept in Opamps Explained

    hi everyone, I am having a tough time convincing myself about the virtual short concept in opamps, As i understand from texts, on the application of a voltage on one of the input terminals of opamp, the voltage at the other input terminal is also forced to match the voltage on the first...
  18. L

    Chemistry Understanding Avogadro's Number and the Role of Carbon-12 in the Mole Concept

    Can someone explain to me what 12 grams of carbon 12 is and how to use avogrados number?
  19. J

    Quick friction concept question

    Homework Statement A box is pulled across a rough horizontal surface with force F. Each time the box moves a distance D, howeveer the angle of F varies. Which angle causes the most/least amount of friction. An angle above/below/horizontal to the surface. Homework Equations...
  20. S

    Understanding Wave Concept: Troubleshooting a Time Gap

    I have got a trouble with wave concept suppose wave is passing through a medium ( let it ,just started) suppose there are four points in the medium (particles) A,B,C,D as soon as A is disturbed even by an infinitesimally small distance , B experiences a forces (forces act...
  21. P

    Solve Pulley Related Rotational Mechanics Problems: Concept Guidance

    how to solve pulley related rotational mechanics problems... please guide me through... the ques are of the kind... mass is attached to a pulley which is further attched to larger pulley... and the moment of inertia of both along wid their radius is given... mass of the load is...
  22. P

    Quick Question - Explain Work Energy Concept

    [Solved] Quick Question - Explain Work Energy Concept Homework Statement Use the work - kinetic energy theorem to find the force required to accelerate an electron (m = 9.11 x 10^-31 kg) from rest to a speed of 1.50 x 10^7 m/s in a distance of .0125 m. Homework Equations W = Fx...
  23. H

    Exploring the Concept of Center of Mass-Energy

    I have learned that the concept of Center of Mass is universal and is applicable everywhere. As per Einstien's Mass-Energy Equivalence there should be a concept of "center of energy" also? For example if I annihilate electron and positron center of mass-energy should apply. The position of...
  24. K

    I have a question about a concept

    i've heard that in a loop the loop environment when the object goes to the top (upside down), gravitational force (mg) will equal to centripetal force(mv^2/r) can anyone explain why this is.
  25. R

    Debunking Your Friend: Why Their Answer to Astronaut Pen Question is Wrong

    i have a concept question that i can't seem to get anybody?? Know?? Lets say you and a friend are wacthing tv and see an astronaut on the space station let go of a pen while he turns to get some paper. What happens to the pen when the astronaugt let's go of it? Your friend says its because...
  26. K

    What Happens to the Center of Mass When a Penguin Moves on a Sled?

    Homework Statement A penguin stands at the left edge of a uniform sled of length L, which lies on frictionless ice. The sled and the penguin have equal masses. (a) Where is the center of mass of the sled? (b) How and in what direction is the center of mass of the sled from the center of mass...
  27. N

    Does General Relativity Explain Mercury's Perihelion Precession and the CMBR?

    Can anyone help me to know that if General relativity explains the perihelion of mercury or the CMBR... If so,how?
  28. M

    Concept of a basis for a vector space

    concept of a "basis" for a vector space I do not understand the concept of a "basis" for a vector space. Here's an example from my practice final exam: Suppose U and V are subspaces of the real vector space W and {u1} is a basis for U and {v1} is a basis for V. If U intersection V = {0}...
  29. S

    Kinematics[polar coordinate] concept problem

    http://p14.freep.cn/p.aspx?u=v20_p14_p_0711201047589252_0.jpg Formula: http://freep.cn/p.aspx?u=v20__p_0711201059233972_0.jpg 1)I need to find out V(\theta). But I remember that r\theta<dot> = \omega = V(\theta) Something seems like contradict Where my concept wrong? How should I...
  30. T

    High concept /sophisticated mathy art, and your other mathy gift ideas please

    Hi :) I was referred here from the xkcd math forums... Basically, I'm looking for a gift for my mathematician boyfriend. He's a voracious reader and has pretty much devoured every single math book in print, so a book is out. I was thinking of some math-based art would be cool, however...
  31. B

    Please HELP Don't Understand Simple Concept on Riemann Sums

    Please HELP...Don't Understand Simple Concept on Riemann Sums Can someone please explain this to me... The number of subintervals in a partition approaches infinity as the norm of the partition approaches 0. That is, ||Triangle|| approaches 0 implies that n approaches infinity. I thought...
  32. J

    What Does the First Law of Thermodynamics Really Imply?

    1. One question ask "Which statement below regarding the First Law of Thermodynamics is best? Select the correct answer." One of the wrong answer is "A system can do work externally only if its internal energy decreases. " What does it mean do work externally? 2. Another question ask...
  33. I

    Concept Question: Rainfall & Draining from Cart

    [SOLVED] Concept Question Homework Statement Q2: Suppose rain falls vertically into an open cart which is rolling along a straight track with negligible friction. The speed of the cart a. increases b. decreases c. doesn't change Q2: Now that the cart is full of water, you poke a...
  34. B

    Questions about the concept of subspace of linear transformation

    Hi all, I have some questions about the concept of subspace of linear transformation and its dimension, when I try to prove following problems: Prove T is a finite dimensional subspace of L(V) and U is a finite dimensional subspace of V, then T(U) = {F(u) | F is in T, u is in U} is a...
  35. C

    Gasoline Engine Turbocharger Concept.

    Conventional turbocharging is done from the manifolds. Or as close to as possible. In the last few years, a company (STSturbo) came out that designed a system for rear mounted turbos, that seems to work well. What I am ultimately trying to figure out is the most efficient way of...
  36. N

    Concept behind levitating object mirage

    I'm sure you've hear or seen this. Its a device that has two bowl shaped mirrors on top of each other, facing each other and the top bowl has a hole cut in the top. The device creates a mirage of any object placed at the bottom that seems to levitate above the hole. How can this phenomena be...
  37. D

    Projectile Velocity: Vx & Accel at Highest Point?

    Hey, I had a basic conception question about projectile velocity. When a projectile reaches its highest point, does the velocity of the projectile equal 0 or does it equal the initial x velocity? I know that Vy=0 at the highest point of a projectile's trajectory, but I'm not sure about the other...
  38. L

    Concept Quilt Help (dealing with Force/Friction)

    Homework Statement Well pretty much i am just starting on my concept quilt and my teacher gave us 9 types of forces that we learn well studied and i need help to understand what she wants me to do. these are the types: Coefficient of Friction contact f Field F Force Diagram Kinetic...
  39. J

    How Can the Net Force Be 10 N with Forces of 4 N and 10 N?

    Two forces, of magnitude 4 N and 10 N, are applied to an object. The relative direction of the forces is unknown. The net force acting on the object __________. _____ can anyone please explain to me why the net force can be 10 N ?? thanks in advance.
  40. H

    Single slit diffraction concept issue

    The standard explanation for diffraction patterns from a single slit employs Huygens Principle and the production of secondary wavelets to form a new 'front'. These fronts reinforce constructively and destructively to produce the pattern. But...if you consider an infinite number of points...
  41. C

    Understanding Simple Pendulum: Solving for Speed in Lowest Position

    The figure shows a simple pendulum of length L = 54 cm and mass m = 2.4 kg. It's bob is observed to have a speed of vo = 4.8 m/s when the cord makes an angle θo = 24°. What is the speed of the bob when it is in its lowest position? I'm having problems with this type of problem, its a new...
  42. F

    Improper integral concept help.

    Ok, my book has the example int from -1 to 2 of dx/x^3 this gets split into int from -1 to 0 of dx/x^3 and int from 0 to 2 of dx/x^3. Now, he had previously determined that the second integral returned positive infinity (diverges) by taking the lim as b approaches 0+. So, the book...
  43. D

    Impulse/momentum concept questions

    Homework Statement (hopefully all can be read) Homework Equations p = mv impulse = m(change in v) The Attempt at a Solution Top Left: My initial guess is they should all be the same since all cars on the roller coaster feel the same affect of gravity for the same distance...
  44. X

    Electricity in wire (again) - concept question

    Hi, I'm trying to understand this concept in order to explain it to a child. Let's say I have a battery with a copper wire attached to each end of the battery terminals. No bulbs, no resistors, etc in circuit - just a wire. The battery creates an EMF that moves the electrons in the copper...
  45. D

    Time: A Material Concept Like Speed and Gravity?

    as we all know high speed and gravity make time run slower so time is affected by material consepts soo time must be a sort of matterial concept like speed and gravity , right?
  46. T

    Max Frequency at the Speed of Light: Clarifying a Puzzling Concept

    Hi, I have wanted to ask someone this for so long, but I know its stupid. Is there a maximum frequency as a side effect of a maximum speed of light? Thinking of light as a pure wave and at a fixed amplitude, it is going to have to travel the distance dictated by the amplitude and frequency...
  47. F

    Concept question-exponential function derivatives (calc II)

    Concept question--exponential function derivatives (calc II) Ok, so there is an example on my textbook that asks for the derivative of y = x^2. --after applying ln on both sides, if finally gets to the lny = xlnx step. But after this step, it just states y'/y = x(1/x)+ lnx(1). I...
  48. D

    New Concept Engine Design: Get Feedback Now

    Hi! I have designed a new concept engine and hope that I can get some useful feedback. http://www.geocities.com/rotarypulsejet . The design is quite radical and I would appreciate any comments that you might have. django
  49. D

    Help on Electromagnetic Induction concept

    This is the material i read from textbook, and it doesn't make any sense to me! can somebody please help me out if they can understand the concept: To understand electromagnetic induction, we need to reconsider the concepts of electric and magnetic fields. A dc current I flowing through...
  50. P

    Time Dilation: Clarifying the Concept for Pat

    I was reading about time dilation and say if we have an inertial S that moves with velocity v in the x-direction with respect to an inertial frame S'. In S' we shoot a light towards a mirror and measure the time from when the original flash takes place to when it returns to it's origin giving us...
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