Contact Definition and 422 Threads

  1. L

    Contact between two rings or two cylinders

    Hello, I would be interrested in comments, references, books, papers and web pages regarding the problem of mechanical contact between two rings. The attached picture describes the geometry of the problem: a ring (tube) is resting on the bottom of a larger ring (tube). These two rings are...
  2. G

    Which direction does the normal contact force act?

    A ring of mass 0.3kg is threaded on a fixed, rough, horizontal curtain pole. A light inextensible string is attached to the ring. The string and the pole lie in the same vertical plane. The ring is pulled downwards by the string which makes an angle "A" to the horizontal, where tan A=3/4. The...
  3. M

    How Is the Average Velocity of 22 m/s Calculated in a Golf Ball Strike?

    A 50g golf ball is struck w a club. the ball leaves the face of the club w a velocity of 44m/s Pf = mvf = (50 x 10^-3 kg) (44 m/s) = 2.2 kg m/s From this I must find the contact time t = change in x /average velocity The change in x in the radius of the ball .05m The average velocity...
  4. C

    Contact forces and action-at-a-distance forces

    Contact forces and action-at-a-distance forces... Are all contact forces the result of action-at-a-distance forces? After all, surely it all boils down to electrostatic repulsions, etc? Thanks in advance.
  5. I

    How much radiation comes in contact with the martian surface?

    How much radiation comes in contact with the martian surface? where can i find more info on this? thanx.
  6. R

    Distinction between forces by contact and forces in distance?

    Is there any real distinction between forces by contact and forces in distance?
  7. R

    Find the maximum frequency for which the block and piston will be in contact

    A block is on a piston that is moving vertically with simple harmonic motion. a)At what amplitude of motion will the block and piston sperate if the period of the piston's motion is 1.18 seconds? b) If the piston has an amplitude of 5.12 cm in its motion, find the maximum frequency for which the...
  8. P

    Independence of friction and area of contact

    Can anyone tell me why friction does not depend on the area of contact??
  9. A

    Direct and Indirect Contact with electrical epuipment

    I have one Question to ask Explain briefly the Difference between direct and indirect contact with electrical equipment. [100 words] thnx
  10. L

    Calculating Contact Forces Between Blocks on a Frictionless Surface

    This problem seemed very straightforward but I've somehow missed something... Three blocks (M1, M2, M3) are in contact with each other on a frictionless, horizontal surface. A horizontal force is applied to M1. If M1= 1.67kg, M2= 2.67kg, M3= 3.78kg, and F= 16.1 N: a) what is the...
  11. W

    Liquid Crystal Contact Lens: The Future of Vision Correction?

    Would it be possible that Opticians will be selling to visually impaired people, Contact Lens, made from a material that has a negative index refraction, that theoretically could be altered with a Liquid Crystal "Eye-Drop" solution? Basically how far are we from a Liquid Crystal Contact Lens...
  12. A

    Behavior of two liquids in contact and a boundary

    Hi, I have a problem that talk about the behavior of two liquids in contact and a boundary that appears between them. I am lack of theory about this situation do anyone of you could help me to find some paper of articles that talk about this? Thank you, Aron
  13. T

    When I made first contact with the alien I was amazed

    When I made first contact with the alien I was amazed by how different it looked, even though it's basic shape resembled mine. For example, we both had 2 arms and 2 hands, but the alien's hands tapered into only two digits on one hand and three on the other. I tried speaking to the alien, I said...
  14. K

    Jerk of the point of contact of a ball rolling on a flat surface

    Hi, I'm working on a kinematics problem of rolling a golf ball on a flat plane (4-position infinitesimally separated solution). The solution sought is to be planar, so we're working in 2D only. This is largely irrelevant though, as I'm facing a rather undergraduate puzzler. I need to...
  15. Ivan Seeking

    Are Governments Preparing for First Contact in Secret?

    http://www.popularmechanics.com/science/space/2004/2/when_ufos_arrive/index.phtml
  16. Nim

    Electrons you come in contact with

    If you tap on a desk, or are walking, does that energy that is being transferred cause electrons in the desk or ground to jump oribitals and emit infrared light? Also, I've read that electrons never touch each other, and that there is actually some space between you and everything that you...
  17. P

    The advantages of contact with aliens

    Given the relativism (conjecturism?) involved with the hypothetical existence of advanced humanoid worlds far older than ours (on a scale of perhaps billions of years), is it not feasible that our inclusion into this "Galactic Club" would give to humanity a significant evolutionary boost...
  18. Sonty

    What is a contact transformation according to Dirac's Lectures on QFT?

    During the last week I've been reading Dirac. I browsed through his Quantum Mechanics and now I'm reading his Lectures on QFT. In both I found the term "contact transformation" and it seems he's the only one to use it because a few people at the faculty have heard about it but they can't give...
  19. R

    Matrix string theory, contact terms, and superstring field theory

    A recent paper details some new insights for the second quantized string field theory. This has some implications for future models, it appears to be quite sound, but this is based on a confined early viewpoint of a first once over reading, no doubt there will be more questions to follow...
  20. G

    How can I contact Michio Kaku?

    does anyone know how i can contact michio kaku! it would be the best
  21. wolram

    How Do Contact Binary Stars Coexist Without Destruction?

    how can (contact binary stars) exist? why is it that one does not destroy the other? where is there center of gravity?
  22. D

    3 Scenarios: How & Why Make/Not Make Contact?

    Greetings ! 3 basic scenarios for you to consider and respond : 1. They come to us. 2. We come to them. 3. Our starships "bump into" each other. Questions : Would you make/not make contact - How ? Would you make/not make contact - Why (for them too) ? (Are you one of "them" ? )...
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