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Slowness (s) is a quantity introduced in Seismology which is the reciprocal of velocity. Thus travel time of a wave is the distance that the wave travels times the slowness of the medium ( in seismology, it refers to different layers of Earth exhibiting different densities ) Thus,
[1] [2] Experiments that attempt to directly probe the one-way speed of light independent of synchronization have been proposed, but none have succeeded in doing so. [3] Those experiments directly establish that synchronization with slow clock-transport is equivalent to Einstein synchronization, which is an important feature of special relativity.
Slow light is a dramatic reduction in the group velocity of light, not the phase velocity. Slow light effects are not due to abnormally large refractive indices, as will be explained below. The simplest picture of light given by classical physics is of a wave or disturbance in the electromagnetic field.
Aristotle suggested that velocity was proportional to force and inversely proportional to resistance, doubling the force would double the velocity but doubling the resistance would halve the velocity (V ∝ F/R). Bradwardine objected saying that this is not observed because the velocity does not equal zero when the resistance exceeds the force.
Velocity of seismic waves in the Earth versus depth. The negligible S wave velocity in the outer core occurs because it is liquid, while in the solid inner core the S wave velocity is non-zero. For the purpose of this explanation, a solid medium is considered isotropic if its strain (deformation) in response to stress is the same in all directions.
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).
Stoneley waves can be partly reflected at sharp impedance contrasts such as fractures, lithology, or borehole diameter changes. Moreover, as formation permeability increases, Stoneley wave velocity decreases, thereby inducing dispersion. The third effect is the attenuation of Stoneley waves. [10]
A tachyon (/ ˈ t æ k i ɒ n /) or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are inconsistent with the known laws of physics.