G Nav Questions - 2
Hi
Need help on these questions please ... On a Mercator chart a straight line is drawn between point A (34 23'S 007 00'W) and point B (34 23'S 009 00'E). Use this info to answer following... The chart distance of the line is 83cm. The scale of the chart at 34 23'S is:- a) 1:954,000 b) 1:1,772,000 c) 1:1,160,000 d) 1:2,150,000 -------------------- The scale of the chart at the equator is:- a) 1:954,000 b) 1:1,772,000 c) 1:1,160,000 d) 1:2,150,000 ------------------- The rhumb line track from A to B is:- a) 090 T b) 090 M c) 270 T d) 270 M ------------------- The great circle track from A to B measured at A is:- a) 086T b) 090T c) 094T d) 099T Any help will be greatly appreciated ! Best regards, Seabass |
Scale = Chart length / Earth Length
Chart length = 83 cm Earth length is departure = ch. long (minutes) x cos lat = 16 x 60 x cos 34°23' = 792 nm change to centmetres : 792 x 1852 x 100 = 146,728,000 cm Scale is 83 : 146,728,000 however should be expressed as 1 : something so divide both sides by 83. Scale is then 1 : 1,768,000. ---------------------- For scale at the equator divide the denominator of the scale (the "1,768,000" bit) by cos of the latitude. 1,768,000 / cos 34°23' = 2,142,000. Scale is 1: 2,142,000 --------------------- They are at the same latitude, rhumb-line track must be 090° or 270°. B is further East so track is 090°. -------------------- The rhumb-line track is 090°. If you draw a diagram the great-circle track at A is greater than the rhumb-line track. The difference is conversion angle. C.A. = 0.5 x ch.long x sin mean lat = 0.5 x 16° x sin 34°23' = 4.5° 90° + 4.5° = 94.5° Any better answer requires diagrams, so you should contact your training povider. Best of luck! Send Clowns Gen Nav instructor, BCFT |
here my answers:
departure: 16 degrees*60miles*cos 34=794 miles 794miles*1.852=1470 km 1470000m:0.83=1772000 answer B. ------------------------------------------------------- then the scale contract at the equator(biger) and expand away from equator 1772000 : cos 34=2137418 answer D -------------------------------------------------------- rhumb line 090T answer A ---------------------------------------- last question: we are in the south!!! 16 degree * sin34=9 degrees 9:2=4.5 degree 090+4.5=94.5 degree |
Just a small point ABO, you're meant to be doing these progress tests yourself!
|
Well, It is written nowhere you have to do the progress tests by yourself. So ABO is in his right to post his homework, and it is good for us , it makes us safer, exactly what the CAA/JAA wants...;)
|
Full marks for initiative ..............
|
All times are GMT. The time now is 16:12. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.