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For example, for visible light, the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200 000 km/s (124 000 mi/s); the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s (56 mi/s) slower than c.
(1 hs = 1 min 40 s = 100 s) 2 hs (3 min 20 s): The average length of the most popular YouTube videos as of January 2017 [15] 5.55 hs (9 min 12 s): The longest videos in the above study 7.1 hs (11 m 50 s): The time for a human walking at average speed of 1.4 m/s to walk 1 kilometre 10 3: kilosecond ks minutes, hours, days (1 ks = 16 min 40 s ...
For instance, an object located at position p at time t 0 can only move to locations within p + c(t 1 − t 0) by time t 1. This is commonly represented on a graph with physical locations along the horizontal axis and time running vertically, with units of t {\displaystyle t} for time and ct for space.
In physics, the special theory of relativity, or special relativity for short, is a scientific theory of the relationship between space and time.In Albert Einstein's 1905 paper, On the Electrodynamics of Moving Bodies, the theory is presented as being based on just two postulates: [p 1] [1] [2]
The faster the relative velocity, the greater the time dilation between them, with time slowing to a stop as one clock approaches the speed of light (299,792,458 m/s). In theory, time dilation would make it possible for passengers in a fast-moving vehicle to advance into the future in a short period of their own time.
The origins of frames S and S′ coincide at time t = 0 in frame S and also at t′ = 0 in frame S′. [2]: 107 Frame S′ moves in the x-direction of frame S with velocity v as measured in frame S. This spatial setting is displayed in the Fig 1-2, in which the temporal coordinates are separately annotated as quantities t and t'.
For example, the CGS unit of force is the dyne, which is defined as 1 g⋅cm/s 2, so the SI unit of force, the newton (1 kg⋅m/s 2), is equal to 100 000 dynes. On the other hand, in measurements of electromagnetic phenomena (involving units of charge , electric and magnetic fields, voltage , and so on), converting between CGS and SI is less ...
For example, for a typical steel alloy, K = 170 GPa, G = 80 GPa and p = 7700 kg/m 3, yielding a compressional speed c solid,p of 6,000 m/s. [11] This is in reasonable agreement with c solid,p measured experimentally at 5,930 m/s for a (possibly different) type of steel. [21] The shear speed c solid,s is estimated at 3,200 m/s using the same ...