AY2 Homework Set 3

Answer all of the five questions.  Show your work for the problems
that need math.

Useful formulas:

     E =h nu (where nu= frequency  & h= 6.6 x10^ -34 Joules/sec )

     c = nu lambda(       c =  3 x 10^8 m/s
     t (moving) = t (rest) * squareroot  [1- (v/c)^2 ] 
     1 Hz = 1/sec or sec-1
     "1 g" = 9.8 m / s^2

1. If you watch your friend moving by, you'll say that her time is
running slow, her length is contracted, and her mass is grater than
her rest mass. How will she perceive her own time, length, and mass?
Why? How will she perceive your time, length, and mass?


2. The famous Martian National Public Station Super Estrella broadcast
at 107.1 FM.  If your were to find it on the radio dial, what would
its frequency be in MHz (megahertz) given that the radio signal has a
wavelength of  2.8 meters?  If Super Estrella also broadcast at  1602
AM (1602 Kilohertz)  what is its wavelength of the radio signal? For
which band  ( FM or AM ) does the radio wave have more energy?


3. A   "clever" student after learning about the theory of relativity
decides to apply his knowledge in order to prolong his life.  He
decides to spend the rest of his life, let's say 55 years, in a
bicycle traveling around the neighborhood at 20 miles per hour.  How
much time will pass on earth, in other words, outside the bicycle in
the "non moving reference frame"?

4. Another maniac-waco student decides to spend time cruising around
the local solar neighborhood at a speed of 0.90 c  (90% the speed of
light).  How much time will go by on earth if in his spacecraft 60
years pass in the student's clock?


5. On a realistic trip to the stars, we could not suddenly jump close
to the speed of light (like in Star Wars) without being killed by the
huge force of such acceleration (too many g-forces to handle).  Thus,
a more realistic trip would have us accelerate at a comfortable rate,
such as "1 g", until we are half way to our destination and then
decelerate at the same rate until we reach our destination.  Explain
why we would be comfortable with this acceleration.  By our own
reckoning, would we notice anything unusual about lengths, masses, or
the passage of time on our spaceship? Why or why not?