A survey rocket of proper length burns in deep space

PHYSICS · Multi-part · Fermi University Physics · Relativity & Gravitation · The equivalence principle and gravity as geometry · The equivalence principle and gravity as geometry

Relativity and Gravitation, Ch Accelerated observers, hyperbolic motion and the equivalence principle

Problem

A survey rocket of proper length 250 m250\ \mathrm{m} burns in deep space, where no gravitational field acts, with constant proper acceleration a=15.0 m s−2a = 15.0\ \mathrm{m\,s^{-2}} along the +x+x axis of the launch frame SS. It starts from rest at x=0x = 0 at t=τ=0t = \tau = 0, with τ\tau the proper time of the rocket's tail clock; the nose is the forward end. Take c=2.998×108 m s−1c = 2.998\times 10^{8}\ \mathrm{m\,s^{-1}} and 1 yr=3.156×107 s1\ \mathrm{yr} = 3.156\times 10^{7}\ \mathrm{s}. ((a)) Working to first order in ah/c2ah/c^2, find the fraction by which the nose clock runs fast compared with the tail clock, and the time by which it gets ahead during one year of tail-clock time. ((b)) When the tail clock reads τ=0.50 yr\tau = 0.50\ \mathrm{yr}, find the rocket's speed in SS (as a multiple of cc) and the elapsed time tt in SS, in years. ((c)) How far behind the launch point, in metres, is the rocket's Rindler horizon?

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