Thursday
August 21, 2014

Homework Help: Science / Geography

Posted by Suzanne on Saturday, October 7, 2006 at 9:18pm.

Losing Your Bearings

1. Begin journey at 40 degrees N by 77 degrees W.

2. Travel 4200 miles with a compass bearing of 130 degrees.

3. Travel 2800 miles with a compass bearing of 180 degrees.

4. Travel 5250 miles with a compass bearing of 90 degrees.

5. Travel 1750 miles with a compass bearing of 0 degrees.

6. Where is your location using latitude and longitude coordinates?

1 degree latitude = 70 miles


I know how to do this, however, your 1 degree latitude is just wrong. It could be that at some latitude, say the starting point, however, as soon as you go N or S it changes. Steps 3, and 5 is a considerable change in latitude, so the 1 degree = fixed value is wrong.
As one goes N or S, the conversion of miles to latitude difference changes. So even in step1, and step 4, it has to be considered. In step 4, you are not at the starting point anymore.

So how does one work this? The easy way is to plot it on a globe. The wrong way to work it is to plot it on a mercator projection (flat map).
The complicated way to solve it is to use spherical trignometry, which I doubt you have been introduced to.
http://star-www.st-and.ac.uk/~fv/webnotes/chapter2.htm
As you can see, the problem is that as the problem states the travel as straight paths, the real path traveled in each step was a curve on the surface of the Earth, not a straight line. Any attempt to measure it as a straight line is wrong. When the distances are large, as in this problem, the error is very large.
Plot this on a globe.


A reminder: Due to the curvature, step one 4200miles at a compass bearing 130 will make a spiral upwards as it is drawn on a sphere. You will have to be careful drawing the line segments to make it a constant angle with Longitude lines.
Wouldn't life be simple if you could use a flat map and ignore the fact that it is totally a wrong representation of Earth's surface?

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Maths - The bearing of A from B is 060 degrees. What is the bearing of B from A...
Maths - What are bearings? Bearings are things that surround rotating shafts to ...
math - A fishing boat leaves port at 11 miles per hour at a bearing of 210 ...
C Programming - How do you reprompt after the user inputs a wrong number into ...
Precalculus - Please check. I did these problems by drawing a graph ... So it ...
Math C30 - An airplane is leaving the first airport (A) at a bearing of 70 ...
calculus - A plane flies 810 miles from A to B with a bearing of 75 degrees. ...
Math - A fishing boat leaves port at 11 miles per hour at a bearing of 210 ...
physical geography - If you begin at 20 degrees 47'36" south and 168 degrees 23'...
geography - if you travel westward along the 80th parallel north of the equator ...

Search
Members