PHYS1002 Study Guide - Final Guide: Length Contraction, Pythagorean Theorem, Invariant Mass
Document Summary
I(cid:374) the theo(cid:396)(cid:455) of spe(cid:272)ial (cid:396)elati(cid:448)it(cid:455), a(cid:374) event is a ph(cid:455)si(cid:272)al (cid:858)happe(cid:374)i(cid:374)g(cid:859) that o(cid:272)(cid:272)u(cid:396)s at a (cid:272)e(cid:396)tai(cid:374) place and time. To record events, each observer has their own reference frame that consists of a set of axes (called a co-ordinate system) and a clock. Each observer is at rest with respect to their own reference frame. Yet observers are often moving relative to each other, and hence their reference frames are too. The acceleration of such a body is zero when measured in an inertial reference frame. This rules out using rotating and otherwise accelerating reference frames. Technically, an earth-(cid:271)ased (cid:396)efe(cid:396)e(cid:374)(cid:272)e f(cid:396)a(cid:373)e is(cid:374)(cid:859)t (cid:448)alid, (cid:271)e(cid:272)ause (cid:449)e a(cid:396)e su(cid:271)je(cid:272)ted to (cid:272)e(cid:374)t(cid:396)ipetal a(cid:272)(cid:272)ele(cid:396)atio(cid:374)s f(cid:396)o(cid:373) (cid:396)otatio(cid:374) a(cid:396)ou(cid:374)d the ea(cid:396)th(cid:859)s a(cid:454)is a(cid:374)d the su(cid:374), but these effects are small and we can neglect them. The relativity postulate: the laws of physics are the same in every inertial reference frame.
