Chapter 26

23) Since the objects changes their dimensions only in the direction
    of the motion,  the height of the observer's friend will
    remain the same  (c).

24) dT = dTo*sqrt(1-(v/c)^2) = 5 min * sqrt(1-0.9^2) = 2.18 min

28)  a)    For the observer in the ship, the distance between Earth and star 
           would be smaller 
            T(ship) = Length*sqrt(1-(v/c)^2)/Time= 5.7 years.
     b)    For the earth observer the time would be    
            T(Earth) = Length/Speed = 4.3/0.6 = 7.2 years 
41) Special theory of relativity shows relativistic effects for the length,
      mass and time (d)