PROGRAM HIZHESAP
IMPLICIT NONE

REAL:: V, r
REAL, PARAMETER:: G=6.674*10**11    !m3kg-1s-2
REAL, PARAMETER:: M=1.989*10**36    !kg

DO r=3*10**15,1*10**16,0.5*10**14
  V=SQRT((2*G*M)/(r))
  PRINT*, "V=",V
END DO
END PROGRAM