When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Time in physics - Wikipedia

    en.wikipedia.org/wiki/Time_in_physics

    t is the time between these same two events, but as measured in the stationary reference frame; v is the speed of the moving reference frame relative to the stationary one; c is the speed of light. Moving objects therefore are said to show a slower passage of time. This is known as time dilation.

  3. Countdown - Wikipedia

    en.wikipedia.org/wiki/Countdown

    The L-minus clock, a mechanical countdown to the time of launch (L−0). Except for the last few minutes, which are highly automated and rigid, scheduled activities rarely take exactly the scheduled time, and the T-minus clock only corresponds approximately to the time until launch. A hold is the suspension of the normal countdown process ...

  4. Fourth, fifth, and sixth derivatives of position - Wikipedia

    en.wikipedia.org/wiki/Fourth,_fifth,_and_sixth...

    Snap, [6] or jounce, [2] is the fourth derivative of the position vector with respect to time, or the rate of change of the jerk with respect to time. [4] Equivalently, it is the second derivative of acceleration or the third derivative of velocity, and is defined by any of the following equivalent expressions: = ȷ = = =.

  5. Entropy as an arrow of time - Wikipedia

    en.wikipedia.org/wiki/Entropy_as_an_arrow_of_time

    When a law of physics applies equally when time is reversed, it is said to show T-symmetry; in this case, entropy is what allows one to decide if the video described above is playing forwards or in reverse as intuitively we identify that only when played forwards the entropy of the scene is increasing. Because of the second law of ...

  6. Minkowski space - Wikipedia

    en.wikipedia.org/wiki/Minkowski_space

    Where v is velocity, x, y, and z are Cartesian coordinates in 3-dimensional space, c is the constant representing the universal speed limit, and t is time, the four-dimensional vector v = (ct, x, y, z) = (ct, r) is classified according to the sign of c 2 t 2 − r 2. A vector is timelike if c 2 t 2 > r 2, spacelike if c 2 t 2 < r 2, and null or ...

  7. Equation of time - Wikipedia

    en.wikipedia.org/wiki/Equation_of_time

    The United States Naval Observatory states "the Equation of Time is the difference apparent solar time minus mean solar time", i.e. if the sun is ahead of the clock the sign is positive, and if the clock is ahead of the sun the sign is negative. [6] [7] The equation of time is shown in the upper graph above for a period of slightly more than a ...

  8. Metric tensor (general relativity) - Wikipedia

    en.wikipedia.org/wiki/Metric_tensor_(general...

    In general relativity, the metric tensor (in this context often abbreviated to simply the metric) is the fundamental object of study.The metric captures all the geometric and causal structure of spacetime, being used to define notions such as time, distance, volume, curvature, angle, and separation of the future and the past.

  9. Action (physics) - Wikipedia

    en.wikipedia.org/wiki/Action_(physics)

    In physics, action is a scalar quantity that describes how the balance of kinetic versus potential energy of a physical system changes with trajectory. Action is significant because it is an input to the principle of stationary action, an approach to classical mechanics that is simpler for multiple objects. [1]