Describe two differences between the orbits of planets and comets.
A lunar lander's robotic arm drops a metal soil-sampling scoop onto the surface of the Moon.
State the equation linking gravitational potential energy, mass, ggg and height.
The gravitational field strength (ggg) on the Moon is 1.6 N/kg1.6 \text{ N/kg}1.6 N/kg. The mass of the scoop is 650 grams650 \text{ grams}650 grams. The scoop loses 1.87 J1.87 \text{ J}1.87 J of gravitational potential energy when it falls.
Show that the scoop falls through a height of about 1.8 m1.8 \text{ m}1.8 m.
The robotic arm then lifts the scoop back to its original height.
State the amount of work done in lifting the scoop.
Explain why the robotic arm would have to do more work to lift the same scoop through the same height on Earth.
A climate monitoring satellite is in orbit around the Earth.
The satellite orbits the Earth with an orbital radius of 7400 km7400 \text{ km}7400 km and an orbital speed of 7.35 km/s7.35 \text{ km/s}7.35 km/s.
Calculate the number of orbits the satellite makes in one day.
