Page 43 - Geography for Secondary Schools Student’s Book Form One

Geography for Secondary Schools
Student’s Book Form One

(iii) Since Mtwara is found in the East of Calculating the longitude of a place using
Tunis, Mtwara’s time will be ahead local time
of that of Tunis by 2 hours (03.00 pm The longitudes of places are calculated
+ 2 hours = 05:00 pm). using their local time. Consider the

Therefore, the time in Mtwara will following examples.
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be 05.00 pm when the local time at
Tunis 10º E is 03:00 pm. Example 1
Find the longitudinal position of Mogadishu
Example 2 whose local time is 4:40 pm when the local

The local time of Washington, D.C. located time at Libreville, Gabon located at 10º E
at 96° W is 05:00 pm Friday. Find the time is 2:20 pm.
and day at Zanzibar 39° E. Given
Given Longitude Time

Longitude Time Libreville-Gabon 10° E 02:20 pm
Washington, DC 96° W 05:00 pm Mogadishu? 04:40 pm
Zanzibar 39° E Required
Solution
Solution (i) The difference in time between

(i) The difference in degrees between Libreville and Mogadishu is given by:
Washington, D.C and Zanzibar will 4:40 – 2:20 = 2:20 hours.
be: 96° +39 ° = 135° (ii) The difference in degrees of longitude

(ii) The difference in time between between Libreville and Mogadishu.
Washington, D.C and Zanzibar will Convert the time difference into
be calculated as follows: minutes.
If 15° = 1 hour 2 hours 20 minutes = 140 minutes.

Then 135 =? The Earth rotates 1° in 4 minutes, how
many degrees will it take to rotate 140
135º × 1 hour = 9 hours minutes?
15 o Difference in longitude

(iii) Since Zanzibar is to the East of 140 min × 1 o = 35 o
Washington, D.C, time will be ahead 4 min
of that of Washington, D.C by 9 hours.
Thus, 05.00 pm + 9 hours = 02:00 am (iii) Since the time of Libreville is behind
Saturday. that of Mogadishu, then Mogadishu
must be located East of Libreville.
Therefore, the time in Zanzibar will Therefore, the longitudinal position
be 02:00 am Saturday. of Mogadishu will be:

10° E + 35° = 45° E.

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GEOGRAPHY (F1) TO PRESS.indd 37 18/10/2024 18:32:36