Newton's law of gravitation, field strength and potential, and the orbits they govern, from low satellites to the geostationary ring. Play the three simulations below. The gamified lessons and the topic Paper 4 practice are live below too.
Simulations · live
Interactive · liveThe inverse-square lawHow the gravitational pull between two masses weakens with the square of their separation.Loads only when you launch, so the page stays fast.
Interactive · liveOrbits and geostationary satellitesGravity as the centripetal force: orbital speed, period and the 24-hour geostationary radius.Loads only when you launch, so the page stays fast.
Interactive · liveField strength and potentialField strength g = GM/r squared and the negative potential well around a point mass.Loads only when you launch, so the page stays fast.
Paper 4 practice · live
Structured questions · with worked solutionsTen original Paper 4 style questionsA full topic set covering field strength and Newton's law, orbits, and potential and energy, each question linked to its lesson, with worked solutions.Open practice →