Doubt Definition and 591 Threads

  1. G

    Does Increasing Density Increase Gravity?

    Keeping the mass constant, if we go on increasing the density of a body its gravity also goes on increasing, like what happens in a black hole,O.K.? But according to the formula F=Gmm/r(square) , only the mass of the 2 bodies is taken into consideration... Suppose 2 spheres are kept at a...
  2. jtbell

    Why Do Non-Native English Speakers Use Doubt Instead of Question?

    I have a doubt about "doubt" Many non-native English speakers here use the word "doubt" where a native English speaker would use "question" instead. Is this just a random confusion of two words with somewhat similar meanings, or is there some pattern to this? Do these people have a native...
  3. P

    Is Diffraction a Result of Wavefront Evolution?

    In single slit diffraction, my professor says that only 2 rays get diffracted. Both at the 2 ends of the slit. no other rays are diffracted. Is this true??:confused: What i think is all rays in the slit get diffracted and not only the 2 rays at the 2 ends of the slit.
  4. P

    A thermodynamic/aerodynamic doubt.

    A thermodynamic/aerodynamic doubt... Hi peeps... Physics forums rock... k now. Before asking my doubt I need to ask small small doubts before the big one... So I guess this question will lead to a hot discussion eventually... Doubt number 1 Is it legal to say that 1 litre of h2o in...
  5. P

    Are There Online Calculators for Composite Material Properties?

    Composite doubt... Composites are so cool and they make me go wild... I have the composite paper only in my 6th semester and I am only in 3rd semester... I was wondering if there are any online calculators to check out the properties of composites. I want to work out with various combinations...
  6. S

    Newbie's Fundamental Doubt: Wave Function & Eigen Functions

    Hi...I am new to this forum. Can somebody clear a fundamental doubt i have?:rolleyes: A wave function has a form found by applying Schrodinger's equation. In steady-state systems, arent the system eigen functions, the wave equation of the system? if so is it the energy eigen function or the...
  7. P

    Pure Rolling: Is Speed of Point of Contact Really 0?

    when we say that in pure rolling the speed of the point of contact is 0 do we really mean it's just absolutely 0 or is it negligible.this may seem strange... but if it's 0 then why does that point ever move.if it ever moves then it's speed is no more 0 ...
  8. L

    Why is Bar Magnet Length Referred to as "2l"?

    folks, in higher secondary books i came across magnet's length that is bar magnet's length is given as " 2l" that is 2 multiplied by l. my question is " why the length is not referred as 'l' the usual way of referring length. please clarify in layman terms. thanks in advance logesh aravindan
  9. P

    Jet Engine Doubt: How Does Temp & Pressure Affect Efficiency?

    A Jet Engine doubt... Hi folks... My aerospace propulsion professor taught me that, in the combustion chamber of a jet engine, during combustion, the pressure instead of increasing, decreases. I have 2 questions. 1) Is it true? 2) If yes, how? How and in what way does temperature, and...
  10. V

    H2O and OH2 Same Species in Complex Entity?

    Homework Statement Are H_{2}O and OH_2 same species when used as ligand in complex entity? Can these be used interchangeably? Homework Equations The Attempt at a Solution
  11. Ivan Seeking

    Scientists cast doubt on Kennedy bullet analysis

    http://www.msnbc.msn.com/id/18709539/ The never ending saga...
  12. P

    The Impact of External Factors on Projectile Range

    Projectile doubt... CHOOSE THE CORRECT ANSWER AND EXPLAIN. What is the nature of proportionality between the muzzle angle and the horizontal distance traveled by a projectile? a) Directly proportional. b) Inversely proportional. c) None of the above. (:biggrin: who says learning...
  13. marcus

    Wiltshire casts doubt on existence of dark energy

    Wiltshire casts doubt on existence of "dark energy" Wiltshire is a minority voice in cosmology, but one worth listening to. Speculation about a "dark energy particle" would be in vain if the appearance of acceleration can be traced to classic GR effects, which is what he tries to do. Wiltshire...
  14. J

    Another doubt regarding wavefunction.

    Will the wave function of a particle be the same in the two cases: 1) When the particle is isolated i.e. as a free or independent particle. 2) When the particle is bonded with other similar particles to constitute a composite particle. For example, consider an isolated quark and a quark...
  15. T

    Help with Rotation Freq of 10kg Ball on 5m String

    A ball with mass m = 10kg is attached to one end of a massless string of length r = 5m.? The other end of the string is fixed about a point. The ball rotates about this point at a frequency of 1 Hz/ While the ball is rotating, the string is reeled in until its length r = 3m. If the system is...
  16. P

    Solving Doubt in Mechanics: Applying Work-Kinetic Energy Theorem

    can we apply wor-kinetic energy theorem when the plates of the capacitor are separated from a distance d to sd
  17. P

    Vortex Doubt: Get Hints & Answers!

    Hey folks... I am goin nuts with this vortex thing. please somebody help me pleasezzzzzzzzzzzzzz my doubts 1.whats bound vortex? 2.Whats horse shoe vortex? 3.Whats free and forced vortex? 4.Whats vortex tube? 5.Whats vortex filament? please give me some hints and any web sites if...
  18. D

    Is Will O' The Wisp's Explanation Accurate?: Doubt About Density

    I love marvel, and recently comic book writers are trying to give us scientific explanations about how their powers work. I'm a fan of density controllers, hence my name, so I'm trying to understand Will O' The Wisp ability: I deleted some parts that are not required for this. The, in order...
  19. P

    Electricity Doubt: Is Electric Field Inside Conductor?

    it is true that no electric field exists inside a conductor but still when we use wire(a conductor)in electric circuits electric field exists inside it.
  20. S

    Comp Sci C++ Pointers: Get Help Understanding Basics & Memory Savings

    Can anyone help me understand the basic use of pointers. I am aware of pointers,yet I feel that a program can be made more easier without using a pointer. My basic dout is that can pointers be used to save memory by dynamic declaration of variables. I thought over it but found that using...
  21. N

    Why Does I3- Exist But Not F3-?

    hey guys , as i was reading some chemistry , i came to know about this weird thing :"iodine" (I3)- ion exists but "flourine "(F3)- does not exist... it seems that there are 2reasons for this ... i searched the internet and it seems tohave nothing ans my textbook do not also have anything on...
  22. S

    How Do Reactivities Compare in Key Organic Chemistry Compound Pairs?

    Discuss the difference in the reactivity between the following pairs of compounds : 1. Benzene and phenol with bromine 2. 1-hexanol and 2-hexanol with chromium trioxide in acid 3. ethylamine and acetamide in dil HCl 4. Sodium methoxide and sodium tert-butoxide with 1- bromopropane Thanks
  23. G

    Why is Division by Zero Not Possible?

    i'm a hight school student and this is a stupid question: why "3 x 0 = 0" and "3/0 = nothing"? should make 0 too. it bothers me from years
  24. V

    Thermodynamics: Understanding the Relationship Between Entropy and Temperature

    In thermodynamics it is said that S = dq/T. Then how can we say that S is directly proportional to T.
  25. A

    Exploring the Irrationality of Pi: Geometrical and Series Proofs

    Hey guys, how do you prove that 'pi' is irrational? I think that it is related to infinite series? Is there any geometrical method?
  26. S

    EM Waves: Source & Coupling - My Little Doubt

    I have a little doubt. EM waves are coupled electric and magentic oscillations. But, to produce an electric field you need a charge and for a magnetic field, you need a moving charge ,but,electric field doesnot exist with a moving charge. So, what is the source of Em waves and moreover how...
  27. V

    Pulley Tension and Normal Force: Understanding the Relationship

    When two objects are tied to some two ends of a string on a pulley hung on a surface, the normal force applied by the surface on the pulley is twice the tension of the string. Why is this so? In fact one of the questions had such a pulley hung on a pulley with the help of a string...
  28. H

    Trivial but heavy doubt in Potential

    Trivial but heavy doubt in Potential! I am having a trivial but heavy confusion with negative confusion of negative sign in the calculation of the potential.When we bring the charge from infinity to radial distance r,the electrical field and displacement are in opposite direction but we just...
  29. D

    T: Exploring Electric Field Behavior

    Growing up from my high school physics where I was taught a simple formula for calculating the electric field. On reading on many physics books , I realized that I could precisely write down the whole electrodynamics on one page.I learned that these electrical influences cannot possibly travel...
  30. N

    Solving the Gravitation Doubt: What Happens When Force Disappears?

    Gravitation doubt... This is supposedly a simple conceptual problem but I still have a doubt about this: A satellite is orbitting the Earth with a constant speed when suddenly the force of gravitation disappears(no explanation as to how that happened!). Then the satellite will: a)...
  31. U

    Can Our Brains Predict the Future?

    How powerfull is the human mind, especially the sub-conscious? Getting up, out of ones chair and walking over to the fridge to get something to eat and returning (if only to read something, slightly less interesting than food,) takes a great deal of physics, spontainious calculation, timing...
  32. S

    Solving a Basic Trigonometry Doubt: Where to Learn?

    I have basic trignometry doubt how to u get 5cos(2t-53.13degrees) from 3cos2t + 4 sin2t. Can someone suggest a site from where I can lean basic trinometry thanks. skan
  33. C

    What is the logic behind L'Hopital's Rule?

    Can anyone tell me, what is the rationale behind L'Hopital's Rule? I just know that how to use it but don't know why it is logic.
  34. T

    A doubt about double integration

    Salutations! This is my first post. I´m writing here because I have a doubt regarding a solved problem of double integration present in a book of mine. I don´t speak english yet ( :frown: ), but I will try to translate the problem to english. Well, here I go: "Calculate int[ (x^2 + y^2) dx...
  35. B

    Can an Accelerating Universe Rotate According to GR Principles?

    I have a doubt. Let consider an universe of only 2 planets with the form of 2 dishes on the same z axis. The 2 dishes are rotating 1 respect to the other. Can we experience centrifugal forces only on 1 of them?
  36. Ivan Seeking

    No doubt : Human Activity Affecting Global Climate Change

    "No doubt": Human Activity Affecting Global Climate Change An interesting link that I had tucked away. http://globalchange.gov/ Here is one story from the link. http://globalchange.gov/
  37. K

    Solving Network Doubt: Finding Computer IPs on WindowsXP

    Im using WindowsXp in LAN. I cud see workgroup computers. But how shall i know the IP of those Computers ?
  38. D

    Reason to believe vs no reason to doubt

    I don't quite support the American expression:"We have a reason to believe" cause I don't think it's enough.What's your pick: -I have a reason to believe? -I have no reason to doubt?
  39. Saint

    Is Fear, Uncertainty, and Doubt Still Being Used Against Linux?

    Fear, Uncertainty, Doubt This is the tactic used by Microsoft against Linux. Very despicable. Linux's OS had been improved a lot, it has everything microsoft has (except Games ).
  40. M

    Several reason for doubt in reality of BB.

    This reasons are: 1) BB expects shaping 3D space from 0D zero point. This impossible. 2) BB expects the expansion of space at the speed of light. If BB began with flashes of the light, then the universe on today look like empty sphere by radius 10 billion light years with the background...
  41. B

    Understanding the Meaning of MeV/C²: A Beginner's Guide to Physics

    [SOLVED] Basic Doubt Hi All,I Want to know the meaning of this formula:MeV/C², Someone can help me?It seems like a big misterious! ;)) Sorry, i´m new in the physics.I beginning to study it,2 weeks ago.Best regards. Blueice88
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