P5a: Satellites, Gravity & Circular Motion

P5a: Satellites, Gravity & Circular Motion

1. Satellites: Object that ORBITS a LARGER object in Space

   • NATURAL: Natural object (Moon)
   • ARTIFICIAL: Man-made object (satellite tv)
     • Geostationary
       • Orbit Time- 24hrs
       • 36000km above equator
         • Fixed position
       • If satellites are placed too close together signals will overlap
         • DIFFRACTION
       • TV/ Phone/ GPS/ scientific research/ long term weather forecasting
     • Low Polar
       • 100km above surface
         • Above poles
       • Faster
         • Orbit Time- 90mins
       • Military spying/ detailed pictures of Earth's surface/ short term weather forecasting

2. GRAVITY keeps Moon in ORBIT AROUND Earth

3. ALL object in the Universe ATTRACT EVERY OTHER object

4. LARGE MASSES give LARGER GRAVITATIONAL FORCE: Sun to Plantes

5. time= distance = 2 r speed speed

6. Centripetal Force: FORCE needed to keep object in a CIRCULAR PATH

   • Planets closer to the Sun have shorter orbit times
     • Gravity makes a satellite accelerate towards Earth
       • Circular orbit: moves at a tangent-Earth is curved
     • Travel faster-bigger gravitational pull
     • Don't travel as far

7. Comets

   • ELLIPTICAL ORBIT
   • Closer to the Sun- gravitational force is STRONGER- FASTER
   • Further from the Sun- gravitational force is WEAKER- SLOWER

8. FURTHER away MASSES have a SMALLER GRAVITATIONAL FORCE

   • F=1 d