Search results
Results From The WOW.Com Content Network
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). For air and marine travel, the knot is commonly used.
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air, is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s.
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 ...
For example, in imperial units, the speed of light is approximately 186 282 miles per second, [Note 3] or roughly 1 foot per nanosecond. [ Note 4 ] [ 15 ] [ 16 ] In branches of physics in which c appears often, such as in relativity, it is common to use systems of natural units of measurement or the geometrized unit system where c = 1 .
It is defined as the distance that light travels in free space in one second, and is equal to exactly 299 792 458 m (approximately 983 571 055 ft or 186 282 miles). Just as the second forms the basis for other units of time, the light-second can form the basis for other units of length, ranging from the light-nanosecond (299.8 mm or just under ...
The Jiffy is the amount of time light takes to travel one femtometre (about the diameter of a nucleon). The Planck time is the time that light takes to travel one Planck length. The TU (for time unit) is a unit of time defined as 1024 μs for use in engineering. The svedberg is a time unit used for sedimentation rates (usually
The equation of time is obtained by substituting the result of the right ascension calculation into an equation of time formula. Here Δ t ( M ) = M + λ p − α [ λ ( M )] is used; in part because small corrections (of the order of 1 second), that would justify using E , are not included, and in part because the goal is to obtain a simple ...
Escape speed at a distance d from the center of a spherically symmetric primary body (such as a star or a planet) with mass M is given by the formula [2] [3] = = where: G is the universal gravitational constant (G ≈ 6.67 × 10 −11 m 3 ⋅kg −1 ⋅s −2 [4])