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. M

    Calculators Is Higher Clock Speed or More Cores Better for a CPU?

    I'm not sure I understand the advantages or disadvantages of each. I imagine Multi-core (in the dual case) as two processors working on the same information to complete the task (reading, writing, whatever) in half the time. I imagine Clock Speed (I'm not sure if this is what you call it...
  2. H

    Atomic Clock Time Dilation Experiment

    Homework Statement Two atomic clocks are synchronized. One is placed on a satellite which orbits around the Earth at high speeds for a whole year. The other is placed in a lab and remains at rest with respect to the earth. You may assume both clocks can measure time accurately to many...
  3. T

    Traveling a light speed from one clock to another

    Einstein is riding the beam of light away from the clock tower so the hands of the clock don't move. Suppose the beam of light he is riding on is going from one clock tower and directly to another clock tower. Would he see the hands of the clock that he is traveling toward move?
  4. G

    One clock on Earth, one on Mars

    Let's say we have two clocks that are synchronous here on Earth. One of the clocks is instantly transported to Mars. What time does the clock on Mars read? Is it ticking slower or faster than the one on Earth? I want to talk about SR here and not the gravity factor of GR. Let's say the...
  5. J

    Puzzle: Exchangeable Clock Positions

    I was hoping some of the brilliant minds here might share their thoughts on the following puzzle: Definition. A valid clock position is exchangeable iff swapping the positions of the minute hand and the hour hand yields another valid clock position. Example. Midnight is an exchangeable...
  6. J

    Does a clock in free-fall slow due to gravitational time dilation?

    I imagine I have two clocks that are synchronised and are sitting a long way from a large massive body. I hold on to clock A and let clock B fall towards the mass. Let's assume that the falling clock B gets close to the massive body but somehow misses it, swings around and travels back to me...
  7. G

    Why Does Stationary Observer See Light Clock Traverse Longer Distance?

    Why does the stationary observer see the spaceship light clock traverse a longer distance? How can you prove this? I don't understand why he sees the light take a longer path. I understand it because you tell me this is so but I don't understand why it actually happens.
  8. W

    Engineering Designing a Circuit to Determine Faster Clock Signal

    Homework Statement You have two clock signals (one is 25/sec,other is 30/sec). Design a circuit that takes both clocks as inputs, determines the faster one within a second, and indicates faster one by lighting an led. The led should remain on until reset by a control signal. You may use...
  9. Z

    Solving Sliding Clock Fun with Two Photons

    I was wondering if someone could help me see where I am messing this up: Lets say we have our train with a relative velocity of .5c, Also suppose it is .816ls tall, and that there is a mirror mounted on the floor, another mirror directly above it, and a third mirror about .577m to the rear and...
  10. N

    Wgat would a light clock measure in free fall?

    Wgat would a "light clock" measure in free fall? I've read in a couple of different books that the similarities between acceleration from gravity and rockets or whatever is only local. Both books said one of the reasons is because with acceleration from gravity two objects in free fall starting...
  11. T

    Engineering Max clock frequency of flip-flop circuit

    Homework Statement Write down the setup and hold inequalities that relate to the second flipflop in each circuit. You should measure all times from the rising edge of CLOCK. Identify which of the circuits will not work reliably and determine the maximum clock frequency for each of the...
  12. A

    Synchronous counter digital clock

    Hi, I am trying to make a digital clock using a synchronous counter. Can anyone please provide me with a proper circuit ? I am having some problems when designing it myself. Thanks.
  13. M

    Pc based digital clock via parallel port using assembly language in tasm

    hi, i have this project and we already have a code and the circuit but it is not working.. it's supposed to display the hours and minutes the problems are: 1. the hour display is not displaying anything 2. the minute displays but it is advanced by one minute so here's the code: TITLE CLOCK.ASM...
  14. C

    Problems with velocity/acceleration involving clock arm

    Homework Statement A traditional watch has a second hand 2.0 cm long, from centre to tip a. what is the speed of the tip of the second hand? b. What is the velocity of the tip at 20s? 40s? and 60s? c. What is it's change in velocity between 15s and 30s? d. What is it's average...
  15. S

    Light Clock Example this is not HW

    Ok I am only a physics undergrad so if this is obvious I am sorry. I understand the concepts of SR pretty well but one thing has bugged me. In the most basic light clock example used to describe the effects of time dilation, where 2 mirrors are placed 1 ls apart on a moving boxcar with an...
  16. C

    Simple harmonic oscillators and a pendulum clock.

    Hey physics forums, this is my first post and frankly I'm having trouble conceptualizing this problem. I know harmonic oscillation is involved, as it is a pendulum. However, I know I have to incorporate g into the s.h.o. equation and I'm not quite sure how to do that. Any help would be...
  17. P

    Speed and Velocity of a clock

    Homework Statement The sweep second hand of a clock has a length of 2.0 cm. Homework Equations a) What is the speed of the sweep second hand tip at the 6 o'clock position? b) What is the velocity of the sweep second hand tip at the 6 o'clock position? The Attempt at a Solution I...
  18. I

    Does anyone have information on how exactly a atomic clock works?

    Does anyone have information on how exactly a atomic clock works? I have had advanced quantum mechanics courses so I am sure I wil understand it. My problem is that I can't find any descriptive materials (with drawings), the wikipedia page is very vague about the different things. So can...
  19. T

    A digital clock shows the time from 00:00 to 23:59 as a string of four digits?

    a digital clock shows the time from 00:00 to 23:59 as a string of four digits 1) how many contain for different strings 4 values e.g. 02:43 i got is as 290 don't think its right since there are 01,02,03,04,05,06,07,08,09,12 = 10 then there are...
  20. X

    Why is the light clock accurate?

    My friend and I have debated about this for some time and, because the vast majority of the scientific community backs him, I presume him to be correct but still do not understand why. I have far from an extensive knowledge of relativity, but I will try not to make a complete fool of myself...
  21. R

    Does gps receiver need synchronization with atomic clock

    with synchronization what the gps receiver does is compute time difference between his current time (synchronized with atomic clock onborad each satellite) and the time tag of a satellite when the signal was sent. This difference gives the travel time of an signal from the satellite and hence...
  22. Z

    Seeking a Decade Counter w/ 1 Input, 10 Outputs & Up/Down Clock

    Hi...can anyone tell me whether there is a decade counter which has only 1 input, 10 outputs and an up/down clock?
  23. bcrowell

    Can't make a clock out of light

    Someone a gazillion times smarter than me says: --Roger Penrose, http://epaper.kek.jp/e06/PAPERS/THESPA01.PDF Reference [5] is Penrose, R. (1965) "Zero rest-mass fields including gravitation: asymptotic behaviour," Proc. Roy. Soc. London, A284, 159-203, first page here...
  24. S

    Processor instruction prefixes (number of additional clock cycles)

    More specifically, this question is oriented towards the Intel 8086. I have this manual that lists the number of clock cycles the 8086 requires to execute each of its instructions, prefixes, et cetera. My question is about repeat string instructions. The REP prefix is listed as 2 clocks...
  25. K

    How Does a Cuckoo Clock Calculate Its Quality Factor and Battery Life?

    Homework Statement Consider a small cuckoo clock in which the length of the pendulum is L, suspending a mass m with a period of oscillation T. The clock is powered by a falling weight (mass = M) which falls 2 m between the daily windings. The amplitude of the swing is 0.2 radians. (A)...
  26. P

    Light Clock Experiment - questions from a newbie?

    Hi all, firstly, I must apologise for my level of physics knowledge and how this might be reflected in my question and the terminology used. I am trying to understand particle physics at an advanced age my neurons are not as elastic as they once were! I have been listening to an excellent...
  27. I

    Question on the reasoning behind the light clock thought experiment.

    I read that the speed of light is independent on the relative velocity of the source. So why is it that the beam zig-zags if there is relative motion between an observer and a light clock. This zig-zagging implies the vector addition of velocities. I know that the speed c is kept constant during...
  28. T

    Time Dilation Gamma Factor: New to STR, Confused?

    i am comletely new to STR, and have just finish reading time dilation. (gamma factor) but i am confuse why to illustrate the factor, light always travel prependiculer to the motion of the "train" i try to apply the same thing when light travel along the motion of the train, then i got...
  29. V

    Gravity and Time Dilation: How Do They Relate?

    sattelite tick slower than an Earth bound clock. Let's say an atomic clock. From what I've gathered so far, the clock aboard the GPS sattelite ticks slower The sattelite is in free fall so the clock aboard the sattelite is in zero G. Is the zero G condition the only condition that cause...
  30. S

    Fluids - Conical vs Cylindrical Water Clock

    I am researching water clocks through history. At some point, it was realized that for the container the water drips from, a conical container with the hole at its point was superior to a cylindrical container with the hole in its side. Could someone explain to me why conical containers are...
  31. S

    Clock Acceleration in a Spacecraft: Calculating Variation Post-Acceleration

    Say if two synchronised clocks are at either end of a spacecraft . when the spacecraft accelerates, the clocks accelerate at different speeds due to length contraction and so are not synchronised post acceleration, according to a non accelerating observer who considered the clocks...
  32. S

    Understanding Light Clock & Time Dilation

    Hi guys, I am having trouble getting my head around the light clock scenario which demonstrates time dilation. I can't help but intuitively feel that it seems like a fault of the clock, rather than time dilation. I hope you can understand what I'm getting at. If someone could try to give an...
  33. P

    Energy-Time uncertainty: observer's clock or observed's?

    How do time-energy uncertainty and special relativity's rules about observers seeing time different for each other interact? Heisenberg's uncertainty principal applies to time and energy: a system existing for a short duration of time has more uncertainty in its energy than one that exists...
  34. B

    Why do clocks appear to run at different speeds when traveling at high speeds?

    I don't understand this: http://casa.colorado.edu/~ajsh/sr/timevbig_gif.html if the mirror is moving fast enough, why won't the light just miss it? why is the light traveling towards at an angle instead of straight?
  35. R

    Atomic Clocks & Moore's Law: Is There a Connection?

    Attached are two diagrams. One describing Moore's law, the other describing the development of atomic clocks since the 50's. Is there a connection between these diagrams, not in the strict graph-math equivalence sense, but in the sense, that conclusions regarding atomic clocks' future accuracy...
  36. R

    Atomic Clock Accuracy: Moore's Law & Beyond

    Attached are two diagrams. One describing Moore's law, the other describing the development of atomic clocks since the 50's. Is there a connection between these diagrams, not in the strict graph-math equivalence sense, but in the sense that conclusions regarding atomic clocks future accuracy...
  37. Y

    Let a clock A be at rest in an inertial frame and let a clock B rotate

    Let a clock A be at rest in an inertial frame and let a clock B rotate around it with constant velocity and constant distance from A. Let v be the velocity of B relative to the inertial frame. Both clocks count how long it takes for B to rotate once. According to clock A, the time it takes is...
  38. liometopum

    Solving Light Clock Question: Calculations for a Relativistic Light Clock

    I am trying to understand the calculations for a relativisitic light clock and am doing something wrong. I am the stationary observer. A light clock goes by at c/2, or 93000 miles per second. The length of the light clock 'rod', which is perpendicular to the line of motion is 186,000 miles...
  39. M

    Time Varying Unit Vectors for Analog Clock - Cartesian and Polar Coordinates

    This is my first post here so please be gentle if I did anything wrong. Also this is for Emag class and its a 4000 level class but this question seems better suited for this forum. I have been doing homework all day and I do not knwo if I am just tired, but I can't get this. Homework...
  40. P

    Whose Clock Slows Down in Relativity?

    So I did a degree some time ago and after watching a programme on TV, I decided to revisit relativity and set myself some questions. One of these was the time difference by spending time on the space station. I worked out that roughly for every 15 mins that pass, the time difference will be 1...
  41. T

    Time dilation in horizontal clock

    hi, when talking about time dilation we base our idea(as i understand) such that; static observer relative to other one claims that lights' path is longer for him/her and since lights' speed is c for each of them time dilation occurs. This is quite obvious in vertical clocks but in horizontal...
  42. L

    Exploring Spacetime Metric for Clock A's Time Interval

    Consider the spacetime metric ds^2=-(1+r)dt^2+\frac{dr^2}{(1+r)} + r^2 ( d \theta^2 + \sin^2{\theta} d \phi^2) where \theta, \phi are polar coordinates on the sphere and r \geq 0. Consider an observer whose worldline is r=0. He has two identical clocks, A and B. He keeps clock A with...
  43. B

    Harmonic Oscillator grandfather clock

    Homework Statement The pendulum of a grandfather clock has a period of 1s and makes excursions of 3cm either side of dead centre. Given that the bob weighs 0.2kg, around what value of n would you expect its non negligible quantum amplitudes to cluster? Homework Equations [/B] The...
  44. B

    Can a light beam stay trapped in a moving cart with ideal mirrors indefinitely?

    Consider a light clock, i.e. two ideal mirrors, mounted in parallel with a vacuum in between, such that, in principle, a beam of light or just a single photon will keep bouncing between the two forever. Now consider the light clock on a cart. If the cart, from the beginning, has constant...
  45. R

    Absolute Time Clock Experiments: Einstein's Special Relativity

    Here is my question, starting from a suggested experiment that reminds a known example that Einstein gave about special relativity including a moving train, two mirrors inside the train and a light beam reflected between the mirrors (this suggested thought experiment described here only reminds...
  46. Drakkith

    Time Dilation Light Clock Example

    I'm missing something here on the light clock example from http://en.wikipedia.org/wiki/Time_dilation. I understand the math on the picture, but I'm missing how that applies to time dilation. Why does the light pulse take on a diagonal path for the moving observer? Is the light pulse still...
  47. W

    Hands of a Clock Constant Velocity?

    Hi Folks, What I have here is a multiple choice question from a practice test. I believe there to be two right answers but the answer key says there's only 1. I'm not looking for anyone to do my homework for me, I just think there is a mistake. Here we go: The hands of a clock _______...
  48. T

    Mass of a Pendulum on a Grandfather Clock

    Homework Statement Can someone please revise my work? It's quite short ) Question: A grandfather clock is designed to have a pendulum which swings a mass at the end of a chain in a horizontal circular motion. The pendulum is designed to swing at 15° off the vertical and to complete one...
  49. P

    Can we make a standard Universe clock?

    Is it possible to make an absolut standard Universe clock? I think it's not easy to make that knid of clock. The effects of gravity and velocity should be removed. If there were a point not moved and no gravity in the Universe, we could measure the time exactly. In the Earth, are we able to...
  50. A

    Is clock become slower or faster

    Hello everyone , While studying Special Theory of Relativity , I got stucked with a conceptual problem and need a satisfying answer desperately . My question is - if there are two observers A and B ...A stays on the Earth B goes in the empty space with the speed say 0.7c . A will measure...
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