View Full Version : General Magnetism Question - ATPL

31st Aug 2007, 07:00
Please help me with this one.

Q. Z is 45 and the T value is 76 units. The values of dip and force H will be:

a) 36.3 61
b) 53.7 61
c) 59.5 66
d) 61.3 36

The correct answer mentioned is a). But I have trouble figuring out the values. For reference:

tan dip = Z/H

and T = H/cos dip

Taken from Ground Studies for Pilots - Navigation page 48 example 7.


31st Aug 2007, 08:18
tan dip = Z/H

H = T cos dip

therefore (tan dip x cos dip) = Z/T

since tan x cos = sin,

sin dip = Z/T; dip = arcsin 0.5921 = 36.3

H = 76 x cos 36.3 = 61.2

So I would say that a) is indeed the correct answer - although I have no idea what the subject is about. Just basic trigonometry and algebra - it is the wont of the JAA to ask rather pointless questions....and answer d) is a deliberate ploy to ensure you RTFQ!

31st Aug 2007, 14:51
Thanks a lot. Had a brain fart for a few moments :)

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