Problem 81, Chapter 37 from Giancoli, “Physics for Scientists and Engineers.”
A spacecraft (reference frame S’) moves past Earth (reference frame S) at a velocity v, which points
along the x and x’ axes. The spacecraft emits light along its y’ axis as shown in the figure below. (a)
what angle does this liight make with the x axis in the Earth’s reference frame? (b) Show that the light
moves with speed c also in the Earth’s reference frame (i.e. given c in frame S’). (c) Compare these
relativistic results to what you would have obtained clessically (Galilean transformations).
y’
S’ Spacecraft
light
x’
v
y
S Earth
light
θ
x
Problem 12.13 from Griffiths, “Introduction to Electrodynamics.”
Sophie Zabar, clairvoyante, cried out in pain at precisely the instant her twin brother, 500 km away, hit
his thumb with a hammer. A skeptical scientist observed both events (brother’s accident, Sophie’s cry)
from an airplane raveling at (12/13)c to the right (see figure below). Which event occurred forst,
according to the scientist? How much earlier was it, in seconds?
12 c
13
500 km
brother
Sophie
Griffiths problem 12.8
A rocket ship leaves earth at a speed of (3/5)c. When a clock on the rocket says 1 hour has elapsed, the
rocket ship sends a light signal back to earth.
(a) According to the earth clocks, when was the signal sent?
(b) According to earth clocks, how long after the rocket left did the signal arrive back on earth?
(c) According to the rocket observer, how long after the rocket left did the signal arrive back on earth?