orbits

• gravity provides the force that allows planets and satellites to maintain their circular orbits
• moons orbit planets, and they have a circular orbit
• planets orbit the sun, and they have an almost circular orbit
• artificial satellites orbit the Earth or any body in the solar system, and have a circular orbit
• • gravity provides the force that allows for satellites to maintain their circular orbit
  • and when an object orbits a body in a circle at a constant speed, the direction of its motion is constantly changing
  • and as velocity is a vector with magnitude and direction, this means the velocity is also constantly changing
• • the force due to gravity is dependent on distance
  • the smaller the distance between the two bodies, the bigger their gravitational attraction
  • the bigger the force of gravitational attraction, the larger the acceleration of the object is orbit
  • a bigger acceleration means a greater change in velocity
  • objects in small orbits travel faster than objects in large orbits
  • this means that to change the orbital speed, the radius of the orbit must also change to ensure a stable orbit
• an orbit is the curved path of one celestial object or spacecraft, around another celestial object.