What is Clock: Definition and 483 Discussions

CLOCK (Circadian Locomotor Output Cycles Kaput) or Clock is a gene encoding a basic helix-loop-helix-PAS transcription factor that is believed to affect both the persistence and period of circadian rhythms.
Research shows that the CLOCK gene plays a major role as an activator of downstream elements in the pathway critical to the generation of circadian rhythms.

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  1. J

    Analysis of accelerated clock

    A clock that moves in a polygonal path is an accelerated clock, correct? It appears that such a clock is usually analyzed using equations derived for inertial clocks. 1. What is the justification for using inertial equations to analyze an accelerating clock? 2. Has anyone used general relativity...
  2. J

    How does a clock signal function

    How does a modern clock signal sychronize a computer command? What does pipeline mean? Lets say that the cpu being considered is an intel product.
  3. A

    Programming atmega32 clock source

    iam using atmega 32 and i want to use external 16MHZ crystal I have figured out the fuse setting for this as lowbuyte=0xFF and highbyte=0Xc9 what i cannot understand is should i set fuse bits before programming or after programming? because as i have specified external crystal as clock source...
  4. A

    Calculating Torque for Parliament Clock Tower Hands at 3:01

    I have attempted this a few times, I got these answers--- 655.44N and 345.144N If anyone can solve this for me it would be appreciated The hour and minute hands of the clock in the famous Parliament Clock Tower in London are 1.7 m and 3.4 m long and have masses of 89 kg and 60 kg...
  5. E

    Exploring the Validity of Dingle's Argument Against the Lorentz Transform

    Some of you may be familiar with Dingle, an "opponent" of SRT. I can condense his argument (the only one I know about anyway) to a sentence or two. Solve the Lorentz Transform for delta-t-prime, then divide through by delta-t. delta-t-prime/delta-t = gamma - gamma*v*delta-x/delta-t...
  6. S

    D flip-flop, S-R master-slave flip-flop, falling edge of clock, NAND

    Homework Statement A D flip-flop is implemented using an S-R master-slave flip-flop that changes states on the falling edge of the clock. Assume that the circuit is fabricated using NAND gates and that each gate has exactly a propagation delay Tpd = 1ns. a) Determine the set-up (Tsu), hold...
  7. E

    Light clock with spaceship moving vertical at .99c

    So what would happen if there was a spaceship moving at 99% the speed of light straight up. The spaceship has a light clock, so a photon of light moving bouncing between 2 mirrors in such a way that the light moves ALMOST in sync with the spaceship moving up. In theory wouldn't the light photon...
  8. N

    One-way speed of light and clock sync

    Ok, i know this makes me look like a crackpot, but suppose for an instant there is an aether or absolute space or whatever! Let me be on a rod that travels tranversely with respect to aether and let me be exactly on the middle point of this rod. I have a GPS device with me and send it upwards...
  9. Q

    GPS satellite and satnav receiver clock synchronisation

    As far as I understand it... Each satellite transmits a signal that the receiver receives. This signal consists of (at least) a satellite identification together with a time-stamp of when the signal was sent and its position at that time. The receiver calculates the distance from the...
  10. 1977ub

    Different Clock Rates Throughout Accelerating Spaceship

    I have been reading a lot of relativity-related material and clearing up a few gaps in my general knowledge. I read something that struck me as off. Perhaps I am missing something. Usenet Physics FAQ -> The Relativistic Rocket http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html...
  11. A

    Could this be a mathematical way to obtain longitude without clock? Please help

    archeoastronomist are bufled at polinesian finding out longitude without a clock here the concept i just found out how to prove: you have a dial with two geared counterotating needles you move by hand every rotation of the sun around you you rotate a needle ten times with which the...
  12. H

    Understanding the Movement of a Unique Clock

    Homework Statement see attachment Homework Equations θ= ω*τ The Attempt at a Solution Nothing. Instead I have some queries about the question itself : 1.Is this a proper clock, will it show the correct time as any normal clock ? 2.what is the angular displacement of one of the...
  13. dbmorpher

    Can entropy be used to measure time?

    Hello dbmorpher here, I was looking at some articles on entropy and wondered, could this be used to calculate time? Entropy is known as the arrow of time, figurative I know but could actually be used to measure. If there was a device that calculated the entropy in a set system couldn't it...
  14. M

    Rate of Change Problem with Clock Hand Position

    Homework Statement "On a certain clock, the minute hand is 8 cm long and the hour hand is 6 cm long. How fast, in cm/min, is the distance between the tips of the hands changing at 9 am?" Homework Equations The Attempt at a Solution I should be able to transform this somewhat...
  15. J

    Lagrangian Dynamics - Grandfather Clock?

    Homework Statement The pendulum of a grandfather clock consists of a thin rod of length L (and negligible mass) attached at its upper end to a fixed point, and attached at its lower end to a point on the edge of a uniform disk of radius R, mass M, and negligible thickness. The disk is free...
  16. U

    Pendulum clock when taken to moon

    Homework Statement A pendulum clock that keeps correct time on the Earth is taken to the moon. It will run a) at correct rate b)6 times faster c)√6 times faster d)√6 times slower Homework Equations The Attempt at a Solution T_{earth} = 2\pi \sqrt{\dfrac{L}{g}} \\ T_{moon} = 2\pi...
  17. P

    Angled light path in moving clock

    1. Ann's light clock uses a single photon that oscillates vertically between two mirrors separated by a distance d. She leaves the space station, accelerates to a constant .2c in a random direction labeled x. For her clock to continue working, the photon must move vertically as before, and...
  18. V

    The light clock and the simple clock

    This is probably a simple question but I can't seem find a convincing enough explanation. Many books on introductory Special relativity use what are called "light clocks" to explain Time dilation. I myself learned this from Arthur Beiser's Modern Physics. This is a simple clock that measures...
  19. J

    Clock Spring Torque: Understanding Input and Output Torque in Winding Mechanics

    I'm winding up a clock spring from the outside and release from the inside. Is the input torque = to the output torque? How would i go about setting up this problem
  20. nukeman

    How does the Circadian clock work in insects like flies?

    Hey all! I am having a hard time finding a few specific answers, so thought I would give you biology nutz a question :) A insect, more specifically, a fly...Can anyone explain the biological/chemical properties of a flies circadian clock? What governs a flies biological clock in terms of...
  21. S

    Where is the Biological Clock in Our Body and How Does it Affect Us?

    where is the biological clock in our body? how does it effect us?
  22. P

    Displacement/ Velocity/ Acceleration Clock Question

    A clock has a 20cm minute hand. From the 6PM mark to the 9PM mark, for the tip of the minute hand, calculate: a) the displacement vector in unit-vector notation b) the average velocity vector in unit-vector notation c) the average acceleration vector in unit-vector notation d) calculate...
  23. A

    Exploring the Paradoxical Light Clock Problem in Special Relativity Analysis

    In a recent thread, a discussion developed on the subject of how we observe light and how this affects our understanding of SR. I called attention to the famous light clock diagrams: http://home.comcast.net/~peter.m.brown/sr/image_gif/sr05-im-01.gif In my view, the problem here is not...
  24. S

    What are the four clock readings?

    The fact that two rocket ships passing each other see the other ships clock run slow fascinates me. But what about total elapsed time? Suppose a person on Earth and a rocket ship on Mars 40,000,000 miles away are at rest relative to each other. They synchronize their clocks so that at t= 0...
  25. P

    Time Dilation - Clock running slower?

    Hi, I am having a hard time understanding one thing about this experiment for Time Dilation. I have one observer on a moving train measuring the time it takes for light to travel a distance d and be reflected back and one observer who is stationary, watching the same events. I understand the...
  26. J

    Determining the Shape of a Water Clock: How to Find the Flow Rate?

    1. Homework Statement Hi guys, A few friends and myself are having some trouble determining how to go about solving this problem for our engineering class. "An emptying tank in which the water level drops at a constant rate in time can be used as a water clock. Consider a tank where the...
  27. J

    Solve Volume of Water Clock Homework

    Homework Statement Hi guys, A few friends and myself are having some trouble determining how to go about solving this problem for our engineering class. "An emptying tank in which the water level drops at a constant rate in time can be used as a water clock. Consider a tank where the...
  28. N

    Instability of an atomic clock

    Hi When I read "popular" papers on atomic clocks, many journalists write that the clock loses 1 second in XX million/billion years. But when I look at some professional papers, people talk about a fractional instability of e.g. 10-14t-1/2, the authors never use the former way of characterizing...
  29. L

    Who came up with the Light Clock Thought Experiment

    Everyone is familiar with the Light Clock, a thought experiment which forms the entire basis of Special Relativity. Through the Light Clock, the Lorentz factor can be derived. So who was the genius who first came up with the Light Clock? Was it Lorentz himself? Or someone else? When did it...
  30. P

    Photon Clock & Time Dilation: Rotating the Clock 90 Degrees

    In the case where you have a photonic clock bouncing a photon between 2 mirrors, if the mirrors are alligned on the vertical axis, bouncing the photon up and down and the overall clock traveling along the horizontal axis, then the whole thing makes sense to me. However, if you were to rotate the...
  31. M

    Question on circular motion, finding out the angular displacement in a clock.

    Homework Statement A clock is showing 3.30. Calculate the angular displacement in degrees from the 12.00 position of the clock to: i the minute hand ii the hour hand I got my minute answer as 180 degree, which is right. But my second answer was 90 degrees, which apparently is wrong! the...
  32. stripes

    Simple Clock App Using Timers

    Homework Statement Application draws a clock. I need it to start at 12:00 and then go to 12:01, then 12:02, and so on, every minute. Then after 59 minutes, bring back to :00 and move the hour up one, etc. Very simple. import java.util.*; import java.awt.*; import java.applet.*; import...
  33. A

    Is it called ring because of a clock?

    Hi, does anyone know why they call a ring a ring. Was it because of Z/(n), where the numbers sort of form a ring in sense? I'm visualizing Z/(n) as a circle like 1 thru 12 on a clock. Or {0,1,2,...,11} if you prefer.
  34. B

    Light Clock Query: Explaining why Light Does Not Escape

    So my uncle recently asked me about a phenomenon that I have been unable to explain, but there that there must surely be a good answer for. A light clock is being observed on an airplane, with the light bouncing back and fourth between the plates of clock. The plates of the clock have the...
  35. A

    Actual clock rate difference between surface of Earth and surface of Moon

    Is there any way in relativity to mathematically compute what the rate difference would be between two identical clocks, one on the surface of the Earth and one on the surface of the Moon? The points on the surfaces to be considered are on the line joining the individual centers of gravity (i.e...
  36. P

    Time on Planet X: Solving for the Alignment of Clock Hands

    Homework Statement A wall clock on Planet X has two hands that are aligned at midnight and turn in the same direction at uniform rates, one at 4.27×10−2 rad/ s and the other at 1.62×10−2 rad/s . At how many seconds after midnight are these hands first aligned and next aligned? Homework...
  37. J

    A clock rate equal to c?

    Hello All, in 4-space, the position is x=(x0,x1,x2,x3), where x0=ct The question is - Can one define the clock rate in the frame of the object at rest as local clock rate = \frac{x_{0}}{t} = c Then all objects, moving with respect to this frame will have clock rates less than c. E.g., a...
  38. H

    Harmonic Oscillations with Escapement [Clock]

    Homework Statement Clock activates escapement every time it passes through the vertical. Escapment under tension from a hanging weight that gives an impulse distance l from the pivot. Energy transferred by this compensates for the energy dissipation due to friction so the amplitude is...
  39. B

    CLD Digital Clock Homework: 555 Timer & BCD Decoder

    Homework Statement I want to make a digital clock on hardware using 555 timer and BCD decoder to 7 segment display. Can anyone help me about the circuit ? Homework Equations The Attempt at a Solution I am using the concept to increment the input of BCD decoder with the help of...
  40. morrobay

    Proper Time : Constant Velocity Clock vs Constant Acceleration Clock

    Homework Statement 3 clocks at to A clock on Earth B clock above Earth 4.66 * 1014 meters C clock above Earth 3.30 * 1013 meters B accelerates to .6 c and arrives at Earth when Earth clock reads 2.6 *106 sec = 30 days With velocity 1.8 *10^8 m/sec with gamma = .8 B clock reads 2.07 *...
  41. K

    Time dilation - Lorentz transformation using light clock

    Homework Statement I am trying to derive the time dilation formula using Pythagorean theorem: L = ct (in clocks rest frame) D = ct'(in observer's frame, the clock moving with velocity u) The Attempt at a Solution So D^2 = L^2 +v^2t^2 c^2{t'}^2=c^2t^2+u^2t^2 Sot'=t*\sqrt{1+v^2/c^2}...
  42. M

    Frame changing and Clock Sync

    Suppose, a long object is at rest in S frame. There is A (On the long object) and B (Near the long object, on the ground) observer in the middle of the long object. There are two clocks located on both end of long object. We suppose, both A and B is at origin of S frame and clocks at some -x and...
  43. A

    Atomic clock used in spaceships

    Hi, Not sure how stupid my question might be. Could anyone please clarify me, why the atomic clock in a spaceship is taken as a reference while explaining a special theory of relativity?. I always wonder how 2 people one outside the spaceship and the other inside it feels about a time in...
  44. R

    3 GPS Satellites & Receiver Clock Synchronization

    Please help me in removing my mistake, since i see 3 satellite required to locate an place on Earth and synchronization of receiver clock with gps satellite. [ I have assumed at any moment a place on Earth will see certain satellite at a certain distance from it in the sky. That is a...
  45. J

    Relativity and The Stopped Clock Paradox

    Might there be anyone here who knows the math to work this one out? Stopped Clock Paradox Simplified "The speed of light is the same for all observers." Scenario The stationmaster has set two synchronized stop-clocks along side the track. The stationmaster placed the clocks exactly 8 μls...
  46. R

    Calculating Time Interval and Speed of Inertial Clock

    Homework Statement In the Home Frame, two events are observed to occur with a spatial separation of 12ns and a time coordination separation of 24ns. A)An inertial clock travels between these events in such a manner as to be present at both events. What timer interval does this clock read...
  47. M

    How does a clock measure time?

    Albert Einstein is quoted as having said "Zeit ist das, was man an der Uhr abliest" ["Time is what a clock measures"]. The question is, as per the title of the thread, how exactly does a clock measure time? When considering this question we need to consider a few things; namely: - what time is...
  48. R

    Time delation or clock malfunction

    Time delation or clock malfunction! Using an example of light clock, it shows light takes more time now to reflect between reflectors due to elongated path as to moving observer, so 1 sec gets elongated. But this could also mean that the clock malfunctions as compared to observer. I mean one...
  49. R

    Time dilation explaination with mechanical clock instead of light clock

    This page http://en.wikipedia.org/wiki/Time_dilation clearly explains time dilation by exampling with the light clock. But how can it be explained if suppose there was a simple mechanical clock instead of light clock. So, now for moving observer there is no light (in light clock) to follow...
  50. N

    How are the clock hypothesis and Unruh effect reconciled.

    How do we reconcile the clock hypothesis in special relativity with the Unruh effect? The first says accelerating clocks tick at the same rate as their instantaneous velocity and the later says an accelerating observer records a temperature rise not observed by an inertial observer. To...
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