enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Braking distance - Wikipedia

    en.wikipedia.org/wiki/Braking_distance

    For higher speeds up to about 100 km/h outside built-up areas, a similarly defined 2-second rule applies, which for 100 km/h translates to about 50 m. For speeds on the order of 100 km/h there is also the more or less equivalent rule that the stopping distance be the speed divided by 2 k/h, referred to as halber tacho ( half the speedometer ...

  3. Hertz - Wikipedia

    en.wikipedia.org/wiki/Hertz

    The hertz is defined as one per second for periodic events. The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" [3] [4] and then adds: "It follows that the hyperfine splitting in the ground state of the ...

  4. Speed - Wikipedia

    en.wikipedia.org/wiki/Speed

    Speed is the magnitude of velocity (a vector), which indicates additionally the direction of motion. Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph).

  5. Tachymeter (watch) - Wikipedia

    en.wikipedia.org/wiki/Tachymeter_(watch)

    Tachymeter scale on a Citizen watch bezel. A tachymeter (pronounced / t æ ˈ k ɪ m ə t ər /) is a scale sometimes inscribed around the rim of an analog watch with a chronograph.It can be used to conveniently compute the frequency in inverse-hours of an event of a known second-defined period, such as speed (distance over hours) based on travel time (distance over speed), or measure distance ...

  6. Orders of magnitude (length) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(length)

    The zeptometre (SI symbol: zm) is a unit of length in the metric system equal to 10 −21 metres. To help compare different orders of magnitude, this section lists lengths between 10 −21 m and 1020 m (1 zm and 10 zm). 2 zm – the upper bound for the width of a cosmic string in string theory. [citation needed]

  7. Orders of magnitude (time) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(time)

    5.4 × 10 83 Qs (1.7 × 10 106 years): The approximate lifespan of a supermassive black hole with a mass of 20 trillion solar masses [21] 10 10 10 76.66 {\displaystyle 10^{10^{10^{76.66}}}} Qs: The scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing an isolated black hole of stellar mass [ 22 ...

  8. Orders of magnitude (numbers) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(numbers)

    1/52! chance of a specific shuffle Mathematics: The chances of shuffling a standard 52-card deck in any specific order is around 1.24 × 10 −68 (or exactly 1 ⁄ 52!) [4] Computing: The number 1.4 × 10 −45 is approximately equal to the smallest positive non-zero value that can be represented by a single-precision IEEE floating-point value.

  9. Orders of magnitude (energy) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(energy)

    10 20 1.4×10 20 J Total energy released in the 1815 Mount Tambora eruption [209] 2.33×10 20 J Kinetic energy of a carbonaceous chondrite meteor 1 km in diameter striking Earth's surface at 20 km/s. [210] Such an impact occurs every ~500,000 years. [211] 2.4×10 20 J Total latent heat energy released by Hurricane Katrina [212] 5×10 20 J