By this formula, the greater its mass, the less a body accelerates under a given force. The masses defined by the above formulas are equal because the latter formula is a consequence of the former, if mass does not depend on time and velocity. Thus, ''mass is the quantitative or numerical measure of a body's inertia, that is of its resistance to being accelerated''.
is kinetic energy a quantitative measure of inertia?
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Answer: no

According to the theory of relativity, no information can travel faster than the speed of light in vacuum, but this does not mean that the refractive index cannot be lower than 1. The refractive index measures the phase velocity of light, which does not carry information. The phase velocity is the speed at which the crests of the wave move and can be faster than the speed of light in vacuum, and thereby give a refractive index below 1. This can occur close to resonance frequencies, for absorbing media, in plasmas, and for X-rays. In the X-ray regime the refractive indices are lower than but very close to 1 (exceptions close to some resonance frequencies). As an example, water has a refractive index of 6999999999740000000♠️0.99999974 = 1 6993260000000000000♠️2.610 for X-ray radiation at a photon energy of 6985480652946099999♠️30 keV (0.04 nm wavelength).
is it possible to have a refractive index less than 1?
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Answer: yes

Mount Kilimanjaro ( /klmndro/), with its three volcanic cones, ''Kibo'', ''Mawenzi'', and ''Shira'', is a dormant volcano in Tanzania. It is the highest mountain in Africa, and rises approximately 4,900 metres (16,100 ft) from its base to 5,895 metres (19,341 ft) above sea level. The first persons known to have reached the summit of the mountain were Hans Meyer and Ludwig Purtscheller in 1889. The mountain is part of the Kilimanjaro National Park and is a major climbing destination. The mountain has been the subject of many scientific studies because of its shrinking glaciers and disappearing ice fields.
is mt kilimanjaro the tallest mountain in the world?
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Answer:
no