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0580/33 May/Jun 2025, Question 21: Standard Form

Cambridge IGCSE Mathematics 0580 · Paper 33 (Core) · Calculator · 8 marks

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The question, in short

Compare five satellite distances from Earth's surface, verify a distance ratio for satellite A versus D, then calculate travel distance and convert a speed to m/s.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (ai) · 2 marks

Order the five given distances, in kilometres, from shortest to longest.

  1. 1As ordinary numbers: A 35 800, B 780, C 1 500 000, D 535, E 20 000
  2. 2Order: 535, 7.8 × 10², 2 × 10⁴, 35 800, 1.5 × 10⁶

Answer535, 7.8 × 10², 2 × 10⁴, 35 800, 1.5 × 10⁶

Part (aii) · 2 marks

Using Earth's radius 6370 km, show that satellite A's distance from Earth's centre is 6.11 times satellite D's, to 2 decimal places.

  1. 1A from centre = 35 800 + 6370 = 42 170 km
  2. 2D from centre = 535 + 6370 = 6905 km
  3. 3k = 42 170 ÷ 6905 = 6.107… = 6.11 (2 d.p.)

Answer6.107…

Part (b) · 2 marks

Find the distance travelled by a satellite moving at 27 000 km/h for 95 minutes.

  1. 195 minutes = 95/60 hours
  2. 2Distance = 27 000 × 95/60 = 42 750 km

Answer42750

Part (c) · 2 marks

Convert a speed of 25 200 km/h into metres per second.

  1. 125 200 km/h = 25 200 × 1000 m per 3600 s
  2. 225 200 000 ÷ 3600 = 7000 m/s

Answer7000

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