ECZ 2021 · O-Level Paper 2 · Question 7 — Earth Geometry

Question from ECZ 2021 · O-Level Paper 2 · Question 7

(a) The points P, Q, R and T are on the surface of the earth as shown in the diagram below. (Take π = 3.142 and R = 3 437 nm)

Diagram for part (a)

(a(i)) Determine the difference in longitudes between points Q and R.[2]

Verified working — step 1

Q (70 N) and R (40 S) both…

(a(ii)) Find the length of the circle of latitude 40° S in nautical miles.[2]

Verified working — step 1

The circle of latitude 40 S has radius R cos 40.

(a(iii)) Calculate the distance TR in nautical miles.[2]

Verified working — step 1

T (60 W) and R (55 E) sit on latitude 40 S, across Greenwich, so longitudes ADD:

(b) The diagram below shows a cone. The shaded part is the thickness of the cone. The internal volume is 34 650 cm3. The internal base area is 3 850 cm2. [Take π = 3.142]

Diagram for part (b)

(b(i)) Calculate the internal height (h) and radius (r).[4]

Verified working — step 1

Volume of a cone V = (13)Ah, so 34650 = (13)(3850)h, giving h = 3 × 346503850 = …

(b(ii)) Given that the cone is 0.7 cm thick, calculate the external volume of the cone.[2]

Verified working — step 1

Add the 0.7 cm thickness to both radius and height:

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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