Orbits of planets and satellitesAQA A-Level Physics: Flashcards

What these 13 flashcards ask

What provides the centripetal force on a satellite?
State the equation for orbital speed.
Does a heavier satellite orbit faster at the same radius?
State Kepler's third law in terms of T and r.
What is the gradient of a graph of T² against r³?
State the equation for the kinetic energy of an orbiting satellite.
State the total energy of an orbiting satellite.
What happens to speed when a satellite moves to a higher orbit?
State the equation for escape velocity.
Does escape velocity depend on the mass of the rocket?
Give three conditions for a geostationary orbit.
Give the radius and height of a geostationary orbit.
Give one use of low orbit satellites.

Exam questions on Orbits of planets and satellites

An Earth-observation satellite is in a circular orbit 600 km above the Earth's surface. Take the Earth's mass as 5.97 × 10²⁴ kg and its radius as 6.37 × 10⁶ m.
Calculate the orbital speed of the satellite. Use $G = 6.67 \times 10^{-11}\ \mathrm{N\,m^2\,kg^{-2}}$ .2 marks
A telecommunications company operates a satellite in a geostationary orbit to relay television signals. A weather-monitoring agency separately uses satellites in low polar orbits.
Explain why a geostationary satellite must orbit in the plane of the equator.2 marks
A student investigates the relationship between the orbital period and the orbital radius of satellites moving in circular orbits around the Earth, which has mass 5.97 × 10²⁴ kg.
Derive the relationship between the orbital period T and orbital radius r for a satellite in a circular orbit, showing that $T^2 \propto r^3$ .3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).