Give me the Alpha Centuri
Example?
Let's consider a space ship
traveling from here to the nearest star (besides our
Sun), Alpha Centuri.
Alpha Centuri's distance is
approximately 4 light
years away according to
us, observers that are stationary with respect the the
earth and Alpha Centuri. For this example, the points of
reference for the time measurements are in the earth's
frame of reference. Thus, the earth will have observers
in the reference frame referred to as the
mover
for the
mover.
Consider a space
ship traveling at 50% c.
We would see a person on this ship travel the distance in
8 years (let
me see how to get this),
since their ship travels half as fast as light, which
makes the trip in 4 years.
This would be different for the space ship, because
the space ship would measure a different time predicted
by the time dilation
equation.
Question:
 Would this time measured for the mover by the
mover be more than, less than or the same as the time
measured for the mover by the stationary frame?
Question:
 The earth measured the trip to take about 8 years.
How long would this trip take according to the space
ship?
(Click on the answer you believe to be correct
below)
 8.00
years
 6.93
years
 5.66
years
 9.24
years
Question:
 According to the space ship, how far, in light
years is it to Alpha Centuri?
(Click on the answer you believe to be correct
below)
 4.00
years
 4.62
years
 2.83
years
 3.46
years
Question:
 The space ship is the stationary frame with the
length measurement because the reference points are at
rest within the earth's frame. Using only the length
contraction formula, how much distance would the space
ship measure for the 4 light year trip? Show me the
Length Contraction equation
again.
(Click on the answer you believe to be correct
below)
 4.00
light years
 4.62 light
years
 2.83 light
years
 3.46 light
years
In fact the time would be about 6.9
years. So according to the mover, the distance traveled
was only 3.46 light years (I want
to see that calculation), not 4 light years as was
registered by the stationary frame. Therefore, space has
been contracted for the mover.
In general, distance is calculated by knowing time and
velocity.
d = vt
Here we will refer to the distance measured for the
mover by the stationary frame as length, l_{o}.
Also remember to set of a table of contents for this
site.
What is L,
L_{o},
v,
and c?
Lesson 3: Length
Contraction
 The
equation.
 Where
does that come from?
 I still don't get it!
Give
me the Alpha Centuri
example.
 So what? There's an
equation. How
do I use the equation in the game?
 Practice
Problems.
 Examples
to aid your practice.
