**Inquiry question: How does the force of gravity determine the motion of planets and satellites?**

**Students:**

● apply qualitatively and quantitatively Newton’s Law of Universal Gravitation to:

– determine the force of gravity between two objects

– investigate the factors that affect the gravitational field strength

– predict the gravitational field strength at any point in a gravitational field, including at the surface of a planet (ACSPH094, ACSPH095, ACSPH097)

● investigate the orbital motion of planets and artificial satellites when applying the relationships between the following quantities:

– gravitational force

– centripetal force

– centripetal acceleration

– mass

– orbital radius

– orbital velocity

– orbital period

● predict quantitatively the orbital properties of planets and satellites in a variety of situations, including near the Earth and geostationary orbits, and relate these to their uses (ACSPH101)

● investigate the relationship of Kepler’s Laws of Planetary Motion to the forces acting on, and the total energy of, planets in circular and non-circular orbits using: (ACSPH101)

● derive quantitatively and apply the concepts of gravitational force and gravitational potential energy in radial gravitational fields to a variety of situations, including but not limited to:

– the concept of escape velocity

– total potential energy of a planet or satellite in its orbit

– total energy of a planet or satellite in its orbit

– energy changes that occur when satellites move between orbits (ACSPH096)

– Kepler’s Laws of Planetary Motion (ACSPH101)

Extract from *Physics Stage 6 Syllabus © 2017 *NSW Education Standards Authority (NESA)