Four velocity and acceleration (25 + 25 = 50 pt) a) Write an explicit form of 4-velocity defined as "= da" /ds, i.e. calculate its components and show that - (-12/0 011-212) - = Hint: Use the infinitesimal form of interval. b) Show that 4-velocity u" is orthogonal to 4-acceleration w" defined in the form of w" = du"/ds. Hint: The square of 4-velocity equals to 1, i.e. dx" dr ds ds = = d8 ds 1