Kathmandu is 30\(^{\circ}\) west of Perth. Using longitudinal distance, what is the time in Kathmandu when it is noon in Perth?
- 10:00 am
- 11:30 am
- 12:30 pm
- 2:00 pm
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Kathmandu is 30\(^{\circ}\) west of Perth. Using longitudinal distance, what is the time in Kathmandu when it is noon in Perth?
\(A\)
\(15^{\circ}\ =\text{1 hour time difference}\)
| \(\text{Longitudinal distance}\) | \(=30^{\circ}\) |
| \(\therefore\ \text{Time Difference}\) | \(=\dfrac{30}{15}\) |
| \(=2\ \text{hours}\) |
\(\text{Time in Perth}\ =\ 12\ \text{pm}\)
| \(\therefore\ \text{Time in Kathmandu}\) | \( =\ 12\ \text{pm}\ -\ 2\ \text{hours}\) |
| \(=\ 10:00\ \text{am}\) |
\(\Rightarrow A\)
The table shows the approximate coordinates of two cities.
\begin{array} {|l|c|c|}
\hline
\rule{0pt}{2.5ex} \textit{City} \rule[-1ex]{0pt}{0pt} & \textit{Latitude} \rule[-1ex]{0pt}{0pt} & \textit{Longitude}\\
\hline
\rule{0pt}{2.5ex} \text{Buenos Aires} \rule[-1ex]{0pt}{0pt} & 35^{\circ}\ \text{S} \rule[-1ex]{0pt}{0pt} & 60^{\circ}\ \text{W} \\
\hline
\rule{0pt}{2.5ex} \text{Adelaide} \rule[-1ex]{0pt}{0pt} & 35^{\circ}\ \text{S} \rule[-1ex]{0pt}{0pt} & 140^{\circ}\ \text{E} \\
\hline
\end{array}
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a. \(13\ \text{hours}\ 20\ \text{minutes}\)
b. \(8:20\ \text{am on Saturday}\)
a. \(15^{\circ}\ =\text{1 hour time difference}\)
| \(\text{Angular distance}\) | \(=60+140=200^{\circ}\) |
| \(\therefore\ \text{Time Difference}\) | \(=\dfrac{200}{15}\) |
| \(=13.\dot{3}\) | |
| \(=13\ \text{hours}\ 20\ \text{minutes}\) |
b. \(\text{Time in Buenos Aires}\ =\ 7\ \text{pm Friday night}\)
| \(\therefore\ \text{Time in Adelaide}\) | \( =\ 7\ \text{pm}\ +\ 13\ \text{hours}\ 20\ \text{minutes}\) |
| \(=\ 8:20\ \text{am on Saturday}\) | |
City `A` is at latitude 34°S and longitude 151°E. City `B` is 72° north of City `A` and 25° west of City `A`.
What are the latitude and longitude of City `B`?
`C`
`text{Latitude of city}\ A: \ -34+72=38°text{N}`
`text{Longitude of city}\ A: \ 151-25=126°text{E}`
`=>C`
City A is in Sweden and is located at (58°N, 16°E). Sydney, in Australia, is located at (33°S, 151°E).
Robert lives in Sydney and needs to give an online presentation to his colleagues in City A starting at 5:00 pm Thursday, local time in Sweden.
What time and day, in Sydney, should Robert start his presentation?
It is given that 15° = 1 hour time difference. Ignore daylight saving. (3 marks)
`text(2 am Friday)`
`text{Angular difference}\ = 151 – 16 = 135°`
`=>\ text{Time difference}\ = 135/15 = 9\ text(hours)`
`text(Sydney is east of Sweden → ahead)`
| `text{Presentation time (Sydney)}` | `=\ text(5 pm Thurs + 9 hours)` | |
| `=\ text(2 am Friday)` |
Pontianak has a longitude of 109°E, and Jarvis Island has a longitude of 160°W.
Both places lie on the Equator.
`d=theta/360 xx 2pir` where `theta=91°` and `r=6400` km (1 mark)
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| i. `text(Shortest distance)` | `= 91/360 xx 2 pi r` |
| `= 91/360 xx 2 xx pi xx 6400` | |
| `= 10\ 164.79…` | |
| `=10\ 165\ text(km)\ text{(nearest km)}` |
| ii. | `text(Latitude)` |
| `4^@\ text(South of Jarvis Island)` | |
| `text(S)text(ince Jarvis Island is on equator)` | |
| `=> text(Latitude is)\ 4^@ text(S)` | |
| `text(Longitude)` | |
| `text(Jarvis Island is)\ 160^@ text(W)` | |
| `text(Rubail is)\ 48^@\ text(West of Jarvis Island, or 208° West)` | |
| `text(which is)\ 28^@\ text{past meridian (180°)}` |
| `=>\ text(Longitude)` | `= (180 -28)^@ text(E)` |
| `= 152^@ text(E)` |
`:.\ text(Position is)\ (4^@text{S}, 152^@text{E})`
An aircraft travels at an average speed of 913 km/h. It departs from a town in Kenya (0°, 38°E) on Tuesday at 10 pm and flies east to a town in Borneo (0°, 113°E).
`d=theta/360 xx 2 pi r` where `theta = 75^@` and `r=6400` km (2 marks)
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| i. | `text(Angular difference in longitude)` |
`= 113 – 38`
`= 75^@`
| `:.\ text(Distance)` | `= 75/360 xx 2 xx pi xx 6400` |
| `= 8377.58…` | |
| `= 8378\ text(km)\ text{(nearest km)}` |
| ii. | `text(Flight time)` | `= text(Distance)/text(Speed)` |
| `= 8378/913` | ||
| `= 9.176…` | ||
| `= 9\ text(hours)\ text{(nearest hr)}` |
| iii. | `text(Time Difference)` | `= 75 xx 4` |
| `= 300\ text(minutes)` | ||
| `= 5\ text(hours)` |
`text(Kenya is further East)`
`=>\ text(Kenya is +5 hours)`
`:.\ text(Arrival time in Kenya)`
`= text{10 pm (Tues) + 5 hrs + 9 hrs}\ text{(flight)}`
`= 12\ text(midday on Wednesday)`
Island A and island B are both on the equator. Island B is west of island A. The longitude of island A is 5°E and the angle at the centre of Earth (O), between A and B, is 30°.
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a. `(0°, 25W)`
b. `8\ text(am)`
| a. | `text{Longitude (island}\ B)` | `= 5-30` |
| `= -25` | ||
| `= 25^@\ text(W)` |
`:.\ text(Island)\ B\ text{is (0°, 25°W).}`
b. `text(Time difference) = 30 xx 4 = 120 \ text(mins)\ =2\ text(hours)`
`text(S)text(ince)\ B\ text(is west of)\ A,`
| `text(Time on island)\ B` | `= 10\ text(am less 2 hours)` |
| `= 8\ text(am)` |
In this diagram of the Earth, `O` represents the centre and `B` lies on both the Equator and the Greenwich Meridan.
What is the latitude and longitude of point A?
`A`
`text(S)text(ince A is) 30^circ\ text(North of the Equator)`
`=> text(Latitude is) 30^circN`
`text(S)text(ince A is) 110^circ\ text(East of Greenwich)`
`=>text(Longitude is) 110^circE`
`:. A\ text(is) \ \ 30^circN 110^circE`
`=> A`