Engineers receive telemetry from a probe moving in a circular orbit around Mercury. The probe travels at 2.8 km/s and completes one orbit in 120 min. The radius of Mercury is 2440 km.
Use circumference=2πr\text{circumference}=2\pi rcircumference=2πr.
What is the height of the probe above the surface of Mercury, to two significant figures?
7.7×102 km7.7 \times 10^2\ \mathrm{km}7.7×102 km
2.0×103 km2.0 \times 10^3\ \mathrm{km}2.0×103 km
4.0×103 km4.0 \times 10^3\ \mathrm{km}4.0×103 km
3.2×103 km3.2 \times 10^3\ \mathrm{km}3.2×103 km
80 exam-style questions on Edexcel GCSE Physics 7.1 The Solar System and gravity, covering 7.1.1 Weight and g on different bodies in space, 7.1.2 The Solar System, 7.1.3 Changing ideas about the Solar System, 7.1.4 Orbits of moons, planets, comets and satellites, and 7.1.5 Gravity and orbital motion. Each one has a worked solution and a mark scheme showing where the marks go.