Question

When it is Friday midday in the prime meridian, what's the time in 180 degree west longitude?

Answer 1

As I'm studying for my exams, I really can't afford to answer on quora, but couldn't resist as I'm doing geography revision.

So, here you go..

Since the earth makes one complete revolution of 360° in 24 hours, that means it passes through 15° in one hour, that also means 1° in 4 minutes.

As you must know Earth rotates from west to east, so every 15° we go eastwards local time is advanced by 1 hour.

Likewise, if you go westwards, local time is retarded by 1 hour.

So, we can conclude that places east of Greenwich gain time as they see sun earlier, whereas places west of Greenwich see the sun later and lose time.

So, if we know GMT, to find local time, we merely have to add or subtract the difference in the number of hours from given longitude.

(Longitude is angular distance which is measured in degrees along the equator east or west of Prime meridian) to cut in short,basically these are vertical lines which pass through both poles.

Now, the answer of your question;

50° towards east..

East means advanced time.

Divide 50° in 3 parts of 15° each and remaining for easy calculation as you know 15° in longitude means 1 hour.

So, it would be

15°(15×4=60min=1hr)+15°(1hr)+15°(1hr)+ 5°(5°×4=20min)= 3 hours 20 minutes. ahead

i.e 12+3hr 20min=03.20 pm

(Note: as mentioned above 1° in 4 minutes, that's why to calculate how much time in 15°, I multiplied it by 4 )

I really hope you understood it and would be capable of calculating it by yourself