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Module 5: Advanced Mechanics
Quick questions on Orbital motion and satellites explained: HSC Physics Module 5
8short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is common orbits used in HSC?Show answer
Low Earth Orbit (LEO). Altitude 200 to 2000 km. Periods 90 to 130 minutes. Used by the ISS, Earth-observation satellites, and Starlink. High orbital speed (about 7 to 8 km/s).
What is atmospheric drag?Show answer
In low orbits (below about km), residual atmosphere creates drag, slowly reducing orbital energy. Satellites must boost periodically (the ISS does this every few months) or eventually re-enter.
What is low Earth Orbit?Show answer
Altitude 200 to 2000 km. Periods 90 to 130 minutes. Used by the ISS, Earth-observation satellites, and Starlink. High orbital speed (about 7 to 8 km/s).
What is geostationary Earth Orbit?Show answer
Altitude about 35 800 km (radius m). Period exactly one sidereal day (about 23 h 56 min). The satellite sits over a fixed equatorial point.
What is medium Earth Orbit?Show answer
Altitude 2 000 to 35 800 km. Used by GPS satellites (about 20 200 km altitude, 12-hour period).
What is q1?Show answer
Define "geostationary orbit" and state its altitude above Earth's surface. [2 marks]
What is q2?Show answer
A satellite is in a circular orbit of radius about Earth. Calculate its orbital speed and period. [4 marks]
What is q3?Show answer
Two satellites orbit Earth: A at and B at . (a) Identify which is faster and by what factor. (b) Find the ratio of orbital periods .