Orbital motion

• What do planets do?

  They orbit the Sun
• What do moons do?

  They orbit planets
• What are artificial satellites?

  Man made satellites that orbit the Earth
• Give 2 examples of artificial satellite?

  Satellites used for Satellite TV , and satellites used for GPS systems
• What allows planets and satellites to maintain circular obrits?

  The force of gravity
• In order for an object to travel in a circular path , what is needed?

  A force that acts towards the centre of the circle
• For planets and satellites, what is the force that acts towards the centre, that allows them to travel in a circular path?

  Gravity
• How does gravity cause objects in orbit to follow a circular path?

  The force of gravity is an unbalance force that results in acceleration towards the centre , causing the object to travel in a circular path
• Describe what happens to an object undergoing a circular motion?

  The acceleration does not cause the object to change speed . The acceleration does cause the object to change direction . This means that object's speed remains the same , but its velocity changes. And the objects instantaneous velocity is perpendicular to the centripetal force
• How is a centripetal force created during an objects orbit?

  As the object orbits, the force of gravity pulls the object in a curved path - creating a centripetal force
• What happens when you change the speed of an object in orbit?

  Changing it speed will cause it orbit to change or fail
• What needs to happen for a smaller body to stay in a stable orbit?

  The smaller body , at a particular distance from the larger body , must move at a particular speed
• What happens to an orbit if its speed changes?

  The radius of the orbit changes
• In terms of it radius, what is needed for a stable orbit?

  The greater the the radius the slower the speed