Form Of The Earth 02 Flashcards
What shape is the earth?
Oblate Spheroid
What is a great circle?
A circle drawn on the surface of the earth whose radius and centre arc are the same as the earth’s (the equator)
What is a small circle?
A circle drawn on the Earth’s surface whose radius and centre arc are not the same as the earth’s
What is the equator?
A great circle whose plane is perpendicular to the Earth’s axis of rotation and which divides the earth into two
What are meridians?
A semi-great circle joining the pole
What is a rhumb line?
A regularly curved lines on the surface of the earth that cuts all meridians at the same angle
How many nm in a degree?
60
How many nm in a minute?
1
List the quadrantal points
045 (NE)
135(SE)
225(SW)
315(NW)
What is a nautical mile (NM)?
The length of arc of a great circle that subtends an angle of one minute at the centre of the earth
(Assuming the earth is a sphere)
What is a Kilometre (KM)?
Generally accepted as one 10,000th of the average distance between the equator and either pole.
What is a Foot?
No relationship with any Earth dimension. Used for Vertical Navigation.
How many KMs in 1 NM?
1nm=1.85km
How many metres/centimetres in a foot?
1ft=0.3048m
1ft=30.48cm
How many feet in 1 NM?
1nm=6080ft
How many feet in a statue mile?
1 mile=5280ft
How many feet in a Kilometre(KM)?
1KM = 3280ft
What do you multiply NM by to find KM?
X 1.852
What do you multiply KM by to get NM?
X0.5396
What do you multiply NM to get Statue miles?
X1.15
What do you multiply feet by to get metres?
X0.3048
What do you multiply Metres by to get to feet?
X3.2808
41nm equals how many KMs?
76
41 miles = how many KM?
66 KM
66nm= how many statue miles?
76
Where is the earth flattest? And where is it widest?
On the polar regions
At the equator by 40nm
The length of ____of a _______\______that subtends an angle of ______minute at the centre of the earth
(Assuming the earth is a sphere)
Arc
Great/circle
One
What is an anti meridian?
The opposite of a meridian
What is the circumference of the earth?
21,600nm
