- A long line of men stand at attention,
spaced exactly 1 meter apart.
The left end of the line is at
x = 0 meters.
At time t = 0, each man
raises his left hand.
- The man standing at the left end of the line,
at x = 0,
has a bad cold.
At time t = 5 meters,
he coughs.
At time t = 10 meters,
he sneezes.
- A cute little doggie runs across the
field at a speed of 0.2c
to the left.
At time t = 0,
the doggie is at x = 8 meters.
The doggie barks at
time t = 5 meters
and t = 10 meters.
- A bird flies just above the ground,
looking for insects.
It moves at speed 0.9c
to the right.
At time t = 0,
when the bird is at x = -3 meters,
it chirps: "TWEET!"
- (optional) The man with a cold flashes a laser
to the right at time t = 8 meters.
It strikes a flower 3 seconds later.
(Your diagram should cover at least
the region x = -4 to x = +11 meters
and t = -1 to t = 16 meters)
Now, Jane and her team are also making careful
measurements of these same events as they
fly past at v = 0.3c
to the LEFT.
Use the Galilean transformations to figure out
the locations and times of these events
in Jane's frame of reference.
Make a (new) space-time diagram which shows
all these events, as measured by
Jane and her team.
- The long line of men raising their
hands lies along the x-axis in
Fred's space-time diagram.
Do those events also lie along the
x-axis in Jane's diagram?
- The man with a bad cold lies
along the y-axis in Fred's diagram.
Does he also lie along the
y-axis in Jane's diagram?
- Consider the cough and the sneeze.
What is the time interval between
these two events according to Fred?
According to Jane?
- Consider these two events:
the bird chirps
the bird meets the dog
What is the time interval between
the events according to each observer?
What is the space interval between
the events according to each observer?
- How fast is the bird flying,
according to Jane?
-
(optional) Where is the laser beam
at time t=11 seconds