10  CLS : CLEAR
20 PRINT : PRINT
30 PRINT "                   Earth Far-Side Tidal Effect Calculator"
40 PRINT "                     Written by Ethan Skyler 11/01/2009"
50 PRINT
60 DEFDBL A-Z  'Sets all numerical variables to double precision
70 REM  Click on QBasic upper left icon. Select Properties. Option. Display Options. Select Window.
80 REM  Font select 14.  Layout Screen Buffer Size Width 80, Height 40.
90 REM  Window Size Width 80, Height 40.

100 REM  Earth Diameter = 7927 mi
110 REM  Earth Radius = 3963.5 mi x 5280ft/mi   er = 20,927,280 ft
120 REM  Earth Object (EO1, EO2, EO3) = 40,000,000 lb.m
130 REM  Earth Object 2 Moon gravity force (eo2mg) = 135.34 lb.f  Average for all Earth's matter.
140 REM  Earth/Moon C/M distance = 238,855 mi  emd = 1,261,154,400 ft
150 REM  Gravitational Constant = 3.321998855540755D-11 lb.f*ft2/lb.m2
160 REM  moonmass = 1.61994D+23

200 CONST er = 20927280
210 CONST eo3mass = 40000000
220 CONST eo2mg = 135.34
230 CONST emd = 1261154400
240 CONST gravconst = 3.321998855540755D-11
250 CONST moonmass = 1.61994D+23

300 degrad = ATN(1) * 4 / 180  'conversion between degrees and radians
310 raddeg = 57.29577951#
320 distance$ = "\        \ ############,.## \                                                \"
330 degree$ = "\        \         ###.#### \                                         \"
340 force$ = "\       \##########,.###### \                                               \"

400 PRINT "     Enter Tidal Position Angle from Earth/Moon centerline (0.1-89.9 deg)"
410 PRINT " Angle is formed between the Earth/Moon centerline extended beyond Earth's c/m"
420 PRINT " and an Earth radius proceeding directly up to EO3's surface position on"
430 PRINT " Earth's far side. "
440 PRINT
450 PRINT
460 INPUT " Tidal Position Angle "; tpa
470 IF tpa <= 0 OR tpa >= 90 THEN GOTO 10:   ' resets page if angle not above 0 or notless than 90 degrees.

500 REM  Calculate triangle T4 to determine the distance EO3 is from Earth's
510 REM  center of matter plus EO3's distance from the Earth/Moon centerline.
520 t4sc = er         't4sc is side c, the hypotenuse of triangle T4 and also an Earth redius.
530 t4ab = tpa        't4ab is angle b of triangle T4 and also the Tidal Position Angle
540 t4aa = 90 - t4ab  't4aa is angle a of triangle T4.
550 t4ac = 90         't4ac is angle c of triangle T4.
560 t4sb = SIN(t4ab * degrad) * t4sc
570 t4sa = SIN(t4aa * degrad) * t4sc

600 PRINT
610 PRINT USING degree$; " T4aa = "; t4aa; "degrees   (T4, angle A)"
620 PRINT USING degree$; " T4ab = "; t4ab; "degrees   (T4, angle B)"
630 PRINT USING degree$; " T4ac = "; t4ac; "degrees   (T4, angle C)"
640 PRINT USING distance$; " T4sa = "; t4sa; "ft        (T4, side a)"
650 PRINT USING distance$; " T4sb = "; t4sb; "ft        (T4, Side b)"
660 PRINT USING distance$; " T4sc = "; t4sc; "ft        (T4, Side c)"

700 REM calculate triangle T5 which reaches to the Moon's c/m.
710 t5sb = t4sb
720 t5sa = emd + t4sa
730 t5sc = SQR((t5sa ^ 2) + (t5sb ^ 2))
740 tant5aa = t5sa / t5sb
750 t5aarad = ATN(tant5aa)
760 t5aa = t5aarad * raddeg
770 t5ac = 90
780 t5ab = 90 - t5aa

800 PRINT USING degree$; " T5aa = "; t5aa; "degrees   (T5, angle A)"
810 PRINT USING degree$; " T5ab = "; t5ab; "degrees   (T5, angle B)"
820 PRINT USING degree$; " T5ac = "; t5ac; "degrees   (T5, angle C)"
830 PRINT USING distance$; " T5sa = "; t5sa; "ft        (T5, side a)"
840 PRINT USING distance$; " T5sb = "; t5sb; "ft        (T5, side b)"
850 PRINT USING distance$; " T5sc = "; t5sc; "ft        (T5, side c)"

900 REM Solution of the force triangle T6 yields the downward-directed
910 REM component of the Missing Force that would be least effective in
920 REM preventing a far side tidal mound from occurring.  Also yielded
930 REM is the horizontal component of the Missing Force that, if present,
940 REM would be most effective in preventing far side tidal mounding.

1000 REM Solve Missing Force rectangle.
1010 t6aa = t5aa - t4aa
1020 t6ac = 90
1030 t6ab = 90 - t6aa
1040 eo3md = t5sc

1100 REM Calculate the moon gravitational force on EO3 (eo3mg) embedded at
1110 REM this point.  Subtracting eo3mg from the average Moon gravitational
1120 REM force experienced by EO2 at Earth's c/m (eo2mg) yields the
1130 REM Missing Force eo3mf.

1200 eo3mg = (gravconst * moonmass * eo3mass) / (t5sc ^ 2)
1210 eo3mf = eo2mg - eo3mg

1300 PRINT USING degree$; " T6aa = "; t6aa; "degrees   (T6, angle A)"
1310 PRINT USING degree$; " T6ab = "; t6ab; "degrees   (T6, angle B)"
1320 PRINT USING degree$; " T6ac = "; t6ac; "degrees   (T6, angle C)"
1330 PRINT USING distance$; " EO3md = "; eo3md; " ft       (Earth Object 3 Moon distance)"
1340 PRINT USING force$; " EO2mg = "; eo2mg; "lb.f      (EO2 Average Moon gravity force)"
1350 PRINT USING force$; " EO3mg = "; eo3mg; "lb.f      (EO3 Moon gravity force)"
1360 PRINT USING force$; " EO3mf = "; eo3mf; "lb.f      (EO3 Missing Force)"

1400 t6sc = eo3mf
1410 t6sb = SIN(t6ab * degrad) * t6sc
1420 t6sa = SIN(t6aa * degrad) * t6sc

1500 PRINT USING force$; " T6sb = "; t6sb; "lb.f  (vertical Missing Force component.)"
1510 PRINT USING force$; " T6sa = "; t6sa; "lb.f  (horizontal Missing Force component.)"

1600 PRINT
1610 INPUT " Calculate Another Far-Side Tidal Position Angle, Y / N "; in$
1620 IF in$ = "Y" OR in$ = "y" THEN GOTO 10
1630 CLS
1640 PRINT : PRINT : PRINT : PRINT : PRINT "                           Press any key to End..."
1650 END