If the radius of the earth is 4000 mi,
(a) How far is Fort Worth, Texas (latitude 33 N), from the equator?
(b) How far is Fort Worth from the North Pole?
(c) Fort Worth is due south of Winnipeg, Manitoba (latitude 50 N). What is the distance between them?
(d) Find the linear speed, due to the rotation of the earth, of Winnipeg.
You've already been given plenty of help. In the very first response, BJHopper said "1deg along a great circle = 2pi4000/360 miles"
so 35 degrees latitude is what distance above the equator? Once you have answered (a), (b) is easy- The distance from the equator to the north pole is, of course, 1/4 the circumference of the earth so to find the distance from Fort Worth to the north pole, subtract its distance from the equator from that. (c) is equally easy. Use the same ideas to find the distance from the equator to Manitoba and subtract the distance from the equator to Fort Worth.
He also said "A point on earth latitude L moves in a circle radius =cos L*4000". You can use that to answer (d).
Thanks Guys for the reply.
The answer for (a) is
(35*2*4000*Pi) / 360 = 2443 miles
I don't Understand why does the book say the answer is 2300 miles.
The answer for (b) is
[ (90*2*4000*Pi) / 360 ] - 2443 miles = 3840 miles
The book says 4000 miles. This result makes sense if rounded to 1 figure. Unlike the mysterious answer of (a)
The answer for (c) is
[ (50*2*4000*Pi) / 360 ] - 2443 miles = 1047 miles
Again, I have no idea why the book says 1200 miles.