Chapter 5, Problem 88AP

A spacecraft starts from being at rest at the origin and accelerates at a constant rate g, as seen from Earth, taken to be an inertial frame, until it reaches a of c/2. (a) Show that the increment of time is related to the elapsed time in Earth's frame by: $d\tau =\sqrt{1-v^2/c^2}dt.$

(b) Find an expression for the elapsed time to reach speed c/2 as seen in Earth's frame. (c) Use the relationship in (a) to obtain a similar expression for the elapsed proper time to reach c/2 as seen in the spacecraft, and determine the ratio of the time seen from Earth with that on the spacecraft to reach the final speed.