Calculation Of Distances And Local Time

Calculation of distance using lines of latitude

Procedures:

1. locate the two places involved
2. find the latitude difference between the two places

Note:    North-North= subtract

                       North-South= add

                       South-North= add

                       Equator-North= add or subtract

                       Equator-South= add or subtract

• multiply the latitude difference by 111km

                       1°=111km( 1° of latitude is approx. 111km on land) 

Example 1

Calculate the distance between  S.Africa(30oS) and Spain(40oN)

Solution:

i) Lat.diff.=30oS+40N=70o

since 1o=111km

therefore,     111×70=7770km

The distance b/w S.Africa and Spain=7,7770km

EVALUATION QUESTIONS

1. What is the distance between place A (lat.20oS) and place B (lat.51oN)?
2. What is the distance between the Equator and Lagos (14oN)?

Calculation of Local Time using the lines of longitude    

Procedures:

1. locate the places involved
2. find longitude difference
3. conversion to time
4. adjust time according to the direction of movement(west or east)

Examples:

1. If the time at town A(long.75°W) is 5.00pm on Friday, what will be the time and day at town B(long.120°E) ?

Solution:

i) Long.diff.=75°+120°=195°

ii) conversion to time=195/15  (since 15°=1hr)=13hrs

iii) adjustment of time according to direction of movt.=5pm+13hrs(add,since it is due east)=6.00am on Saturday

EVALUATION QUESTION

Explain how to use longitude to calculate local time

GENERAL EVALUATION

When it is 2.00pm at GMT; what is the time in

1. Ethiopia (45oE)?
   1. Los-Angeles (75oW)?
   1. Nigeria (15oE)?

                                                                                                                                                                                     READING ASSIGNMENT

Essential Geography, O.A. Iwena, Pages 17-19.

WEEKEND ASSIGNMENT

1. If the time at the Greenwich Meridian is 11.00 am, what would be the local time at a place 75⁰ W?  (a) 6:00am (b) 6:00pm (c) 7:00am
2. Which of the following is not a characteristic of lines of longitude? They …… (a) converge at the poles (b) run from east to west (c) run from north to south
3. Latitude 66 1/2⁰S marks the…….. (a) Antarctic circle (b) Arctic circle (c) Tropic of cancer
4. What is the approximate distance of town X from the equator, if it is located on latitude 14⁰N? (a) 1232 km (b) 1555km (c) 1675km
5. Which of the following planets has twelve satellites? (a) Jupiter (b) Mercury (c) Saturn

THEORY

Attempt questions 3(a), 3(b), and 4(b) on page 21 of Essential Geography.