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. Borek

    Switching clock synchronization off under Debian

    I am working on a project* in which I need to fake a pendrive so that it looks like if it was used for several years. That means copying files, making directories, removing them and so on. It needs to be done in such a way that all dates looks OK, which makes it less trivial than it sounds...
  2. Grimble

    I Is a clock on the equator time dilated?

    Clocks in orbit are time dilated due to their orbital velocity. Do we measure a similar effect for clocks on the equator when measured against clocks at the poles?
  3. J

    How to slow down a battery wall clock from the 1960's

    I have 2 new battery operated clocks that have been lying on the shelf for 50 years never used them both run after I oiled them, they have a motor that winds up a spring and the a little spring that goes around in circle one end fastened to shaft the outside end to a fixed point this rocks back...
  4. W

    Length of time needed to measure digital clock accuracy

    On a piece of equipment, I purchased new, the digital clock ran slow. The second digital clock that was installed ran slow---it lost approximately 4.1 minutes in one month. Below is what I sent the Service Manager who I understand thinks it is possible to test the newly installed clock...
  5. T

    B Why does GPS require an accurate clock?

    Why do GPS need a cesium clock accurate to 10ns? Is this strictly for time keeping or is there some synchronization between satellites?
  6. Sorcerer

    I GR: Does Clock Hypothesis Apply?

    *This question is beyond my education, but if you need to post graduate level math, feel free to, and if it requires changing this to A level, be my guest* So in SR, we assume that time dilation does not depend on acceleration, but only instantaneous speed. But in first learning about the...
  7. R

    B Pulsar Clock: The Mystery of Slowing Rotation in a Spaceship

    If a pulsar with a period of exactly 1 second was put in a spaceship and accelerated up to V where would the energy come from to slow the rotation of the pulsar ?
  8. T

    Making a Binary Clock - Get Answers to Your DIY Questions

    I want to make a binary clock and I found a place with info of "how to" do it but since I'm total noob at electoronics I need some thing clearing some stuff 1st here's the link http://www.instructables.com/id/LED-Binary-Clock-20/ So far I'm still in a process of obtaining the stuff, mostly...
  9. F

    B Length contraction applet - have they got it wrong?

    Hi, I was browsing the internet for interactive simulations illustrating special relativity concepts. It seems to me that those in this http://kcvs.ca/concrete/visualizations/special-relativity are mostly nice and clear, although not very "chrome-friendly" (I have to use firefox to play their...
  10. B

    How does warming the hoop affect the frequency of an escapement in a clock?

    Homework Statement I have an escapement in a clock. It given shape is hoop with radius 5mm, mass 0.01g and has a frequency 5Hz. For how much does the frequency change if we warm the hoop for 20K? α= 1.2 ⋅10^{-5} K^{-1} Homework Equations...
  11. Aleberto69

    B Lag of a clock coming back to its initial position (Twins Paradox)

    Hello, I'm a beginner on SGR and I'm struggeling with this, probably, simple problem. I'm interested on exploring Field Theory ( relativistic) so I started reading http://www.elegio.it/mc2/LandauLifshitz_TheClassicalTheoryOfFields_text.pdf which was suggested and reccomended by a PF's member...
  12. S

    B Light Clock Traveling in Z Direction

    Hi, I'm studying GR these days. But then I got to thinking about something about SR and got kinda stuck. I know that if a light clock is moving in the x direction(from left to right), the light beam has to traverse more space and then you will see this person's clock running slower in the...
  13. J

    Clock Notation of Star-Delta 3-phase transformer

    Homework Statement Homework Equations Dot is A2. A1-A2 of star is in phase with A1-A2 of delta The Attempt at a Solution I'm getting answer as Y-Delta - 1. Assuming Y is HV. How is C right answer?
  14. J

    Clock face notation of a Transformer's "Vector Group"

    Hi, I'm studying transformer and am a bit confused. Say for vector group: Dy11, I guess it's the line voltage of LV leads the Line voltage of HV by 30 degrees. Book says phase angle. The phase angle is line voltage right, since the phase voltage of HV and LV will always be in phase with each...
  15. B

    I "Banana clock shapes" puzzle on social media

    I looked for an answer to this question other places but found none. There is a puzzle going around that people are getting the answer wrong to. No surprise there. According to the proofs I found for it on the internet, my assumptions were true and I did arrive at the right answer (38...
  16. G

    I GPS and Cs atomic clock question

    Ok, so pardon my ignorance if this can found easily online but I have these few questions. I was actually reading quite a complicated article about GPS and relativity but it had too much maths in it for my abilty. Ok, first of all, apart from the complicated details regarding the workings of...
  17. T

    Torque On a Clock Hanging from a Nail

    Homework Statement A square clock of inertia m is hung on a nail driven into a wall (Figure 1) . The length of each side of the square is ℓ, the thickness is w, and the top back edge of the clock is a distance d from the wall. Assume that the wall is smooth and that the center of mass of the...
  18. T

    B What is a Clock? Syncing Technologies Explained

    How do we decide what is a clock and how do clocks that rely on different technologies stay synchronized?
  19. B

    I Clock hypothesis, gravity time dilation and Equivalence Principle

    1. The Clock Hypothesis states that the rate of a clock does not depend on its acceleration but only on its instantaneous velocity. This has been experimentally verified at very high accelerations. 2. A clock in a gravitational field experiences time dilation and runs slower that one not in a...
  20. Fb.Researcher

    Prove 2 and 3 state clock model is equivalent to Potts model

    Homework Statement A p-state clock model is a spin model in which states can be viewed as hands of a clock! Now knowing the models we should prove these two models are equivalent for ##p=q=2## or ##p=q=3## Homework Equations Potts model is described by $$ H = -J \sum_{<ij> } \delta_{...
  21. N

    Find how far ahead a grandfather clock gets after a period of time

    Homework Statement A pendulum shortens due to a change in temperature, decreasing the length L and therefore period T. How many seconds ahead does the clock get in 24 hours? We assume that the grandfather clock is completely accurate at a normal pendulum length. Li = 1.3 m ΔT = -10°C Homework...
  22. D

    I Einstein's light clock thought experiment

    I'm an engineer who has an amateur interest in physics. I have been reading about Einsteins light clock experiment. I understand the principal that when a light clock on a train etc is moving relative to a standing still observer then the light must travel a longer distance per tick. given that...
  23. F

    I What happens to local clock when many observers are moving wrt each other?

    I looked around the net and couldn't find an answer to this particular setup: Suppose I am at rest with two friends (friend A and friend B). We all have a clock. All three clocks are synchronized and tick at the same rate. Now one of my two friends (friend A) starts his rocket engine and leave...
  24. Alfredo Tifi

    I Einstein clock syncing with one way light emission absorber

    Two spaceships with their engines shut off and identical radio receiver-amplifier-reemitting devices are in the empty space, very far from each other and from any celestial body. The lag time from absorbing to reemitting in the device is vary small compared to the return time of the signal (2t)...
  25. M

    A clock problem [equation solving]

    Homework Statement [/B] At what time after 4:00 will the minute hand and the hour hand of a clock first be in the same position? Homework Equations Angular Velocityminute hand=12w Angular Velocityclock hand=1w[/B]The Attempt at a Solution For attempting a solution first I should understand...
  26. Arkalius

    I Question about GPS clock synchronization

    I'm familiar with the combined effects of special and general relativity making clocks on GPS satellites tick faster than those on Earth by about 38 microseconds per day. The clocks on the satellites are adjusted to stay in sync with Earth clocks, and all is fine an dandy in that regard...
  27. Dimani4

    I Moving Clock: Lorentz Factor Calculation

    Hi guys! I want to thank to all the guys which helping us to understand the beauty and mystery of the relativistic theory. Here I just want to share the calculation of Lorenz factor for the moving clock in the frame of reference of the "stationary" observer. This time the clock is not...
  28. Dimani4

    I Clock Synchronization: Jack & Jill's View

    Hi, Here me again. I have a question about clock synchronization. Suppose we have train with Jill with two clocks and Jack on the ground. As seen from the ground by Jack, the two clocks on the train (which is moving at v in the x-direction) are running slowly, registering only seconds for each...
  29. J

    Changing the coordinate system of the hands of clock

    I want to understand what changing coordinate system means for hands of clock. Let's say the clock only has hour and minute hand. It can move let's say just in the upper 180 deg. of the clock (as shown in the figure). The area between the two hands is V1, and the rest is V2. Depending on the...
  30. C

    Iodine Clock Kinetics: Which Mechanism is Supported?

    1. Homework Statement An iodine clock kinetics experiment was performed by varying the composition of reactant solutions and measuring resulting rates of reaction (based on the data given, I have determined the rate law to be R = [I-]1[S2O82-]1). Which of these four proposed mechanisms below...
  31. John S

    Einstein's Clock: See What at Speed of Light?

    Question: If the hands on a stationary clock will appear to stop when traveling away from it at the speed of light, what would you see if traveling towards it at that speed?
  32. A

    News What is the current time on the Doomsday Clock?

    The new setting is 2 1/2 minutes to midnight. The only year they made it closer was 1953, after the first H-bomb was detonated, when they set it to 2 minutes to midnight. They have a PDF which explains their reasons. I do not necessarily endorse their reasoning. But it's good to think about our...
  33. Crowxe

    I Relativity's "time dilation" or clock accuracy alteration

    i've seen the double slit experiment and the delayed choice . my mind rejected the conclusion, but the experiment setting and configuration of delayed choice is rational and holds water so i accepted the experiment outcome even if it means the world isn't real. i had to give that intro that...
  34. T

    Distributing a clock signal using a clock fanout buffer

    hi, im trying to distribute a clock signal using a clock fanout buffer. I have an oscillator and i need to get its clock signal to 4 other devices. My first idea was to supply the clock signal of the oscillator to a clock buffer. I have chosen this clock buffer...
  35. K

    Difference between a clock and a series of radar pulses

    Homework Statement I have been working through “Basic Concepts in Relativity and Early Quantum Theory” by Resnick and Halliday. I've read about and done most of the problems about time-dilation, length-contraction, and Doppler effect. But then I got to problem 2-76, and I’ve been swirling in...
  36. ikihi

    Building a Clock from a Spring: Exploring Potential Energy

    Homework Statement You are in a spaceship far from any other objects, and you want to build a clock. You decide to build your clock out of a spring with a mass attached to it. You use a spring with spring constant k = 138 N/m, and you initially displace the mass a distance x=25.0 cm from...
  37. V

    How can I accurately determine the time gained or lost by a clock?

    Homework Statement Homework EquationsThe Attempt at a Solution I usually have trouble with these clock problems . In this problem I can certainly rule out option d) . I considered a simple situation in which initially the clock is at 12' o clock . After 65 minutes , the minute hand would...
  38. T

    Can I Use a Frequency Synthesizer to Create a 28.8MHz Clock Signal?

    hi, i need a 28.8MHz clock signal (digital/square wave). Unfortunately this specific frequency is hard to get so i need to make one myself. I guess the keyword here is "frequency synthesizer"? Or how would you approach this? (to get the 28.8MHz clock signal out of other more commonly available...
  39. pioneerboy

    Electronics Building an Alarm Clock with Basic C Programming Skills

    I'd like to build my own reliable alarm clock, but I don't have any knowledge in electronics and no fancy equipment, only some humble C programming experience. What do I need and what do I need to know to build one myself. Thanks very much.
  40. T

    Split clock signal (provided by oscillator)

    hi, i was wondering how its possible to split a clock signal provided by an oscillator in order to use it to drive multiple devices with this one split clock signal. Let's assume we have a kind of USB device (like an USB stick), that gets its clock signal from an oscillator. Let's say i would...
  41. Matternot

    I Special relativity timebomb on distant planet 'paradox'?

    I thought of this 'paradox' which is somewhat similar to the twin paradox but can't be explained by a lack of symmetry etc. It is very similar to many paradoxes I have heard before of which the resolution is known (which is why I am mostly sure this can be resolved) Bob is looking through his...
  42. K

    I Does Special Relativity Apply to a Moving Clock?

    A Moving Clock runs slow. But, If time t has elapsed in the S frame, does SR apply to a clock moving with speed u in the x-direction in the S frame, relative to the S frame? Or does SR apply only when the clock is in another reference frame S' moving in the x'-prime direction, given that...
  43. V

    A Time dilation for the clock in the orbit

    Suppose that we want to compute the total time dilation for a clock located in an orbiting satellite relative to the clock in our cell phone on the ground. Consider two different approaches below. 1. Use special relativity and compute time contraction due to velocity. Use approximation of...
  44. AndyWeb

    B Unlocking the Universe: A Planck Clock Exploration

    Hello, I was watching watch videos lol. I bought a new automatic watch and I was interested to see how they work, here is a nice YouTube video; There are various types of watches / clocks. Sun dial, mechanical, kinetic, quartz and of course atomic. They all, however, measure time kinda...
  45. Grayman

    B Problem with the atomic clock and time dilation

    The atomic clock is used as evidence of time dilation and to provide more evidence that light speed is invariant. The problem I have with this is that the clock uses frequency and light. It has a feedback loop that is supposed to correct for inaccuracies but the entire loop will obviously be...
  46. L

    Analog clock algebra word problem

    Homework Statement define the time in an analog clock up to the second. The time needs to be such that the minute hand, is at the exact same position as the hour hand. This position of the hands needs to be between 10th and 11th hour. Homework Equations 3. The Attempt at a Solution [/B] I...
  47. G

    I Exploring Time Dilation: The Effects of Temperature on Clocks

    Hi. Temperature is movement on a microscopic scale, and movement leads to time dilation. So what happens if we heat up a clock? Let's for example assume a pendulum with negligible thermal expansion, such that all other thermal effects on the period can be neglected. Will it run slower? What...
  48. M

    I GPS Data Availability - Positions, Clock Readings etc.

    Hi there! Does anyone know where data from the GPS is available? Any data at all - positions. clock readings anything like that. Many thanks!
  49. E

    I Leading and lagging clock times in Lorentz Transforms

    Someone posted this link to a paper I really appreciated. http://www.hindawi.com/journals/physri/2015/895134/ But doesn’t the author have the wrong sign on the relative velocity in his Lorentz Transform associated with his figure 2b? And if so, doesn’t that reverse his conclusion that “leading...
  50. ZawL

    I Clock Thought Exp: A Light-Year Time Paradox

    This is a thought experiment I came up with this evening. It must surely have been considered before but I couldn't find any reference and I've come up with it independently. NASA has positioned a clock in Earth's thermosphere that can be viewed from outer space with a powerful enough telescope...
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