Chapter 27
Special Relativity
By Boundless
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Galilean invariance or Galilean relativity states that the laws of motion are the same in all inertial (or non-accelerating) frames.
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Special relativity is based on Einstein's two postulates: the Principle of Relativity and the Principle of Invariant Light Speed.
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The speed of light in vacuum is a universal physical constant crucial to many areas of physics.
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The relativity of simultaneity is the concept that simultaneity is not absolute, but depends on the observer's reference frame.
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Time dilation is an actual difference of elapsed time between two events as measured by observers moving relative to each other.
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The twin paradox is a thought experiment: one twin makes a journey into space and returns home to find that twin remained aged more.
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Objects that are moving undergo a length contraction along the dimension of motion; this effect is only significant at relativistic speeds.
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A velocity-addition formula is an equation that relates the velocities of moving objects in different reference frames.
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Relativistic momentum is given as
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In special relativity, as the object approaches the speed of light, the object's energy and momentum increase without bound.
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Antimatter is composed of antiparticles, which have the same mass as particles of ordinary matter but opposite charge and quantum spin.
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Relativistic kinetic energy can be expressed as:
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Special relativity changed the way we view space and time and showed us that time is relative to an observer.
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We live in four-dimensional space-time, in which the ordering of certain events can depend on the observer.
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Gravity is a geometrical effect in which a metric matrix plays a special role, and the motion of objects are altered by curved space.