Physics 4: Mod 2 - Gravitation

Physics 4: Mod 2 - Gravitation

1. Newton's Law

   • Universally attractive force between all matter
   • Force between point masses
   • Inverse square law
     • F=\(\frac{Gm_1m_2}{r^2}\)

2. Gravitational Field Strength

   • 'Force fields'
   • Field line representation
   • 'g' = force per unit mass
     • g=\(\frac{F}{m}\)
   • 'g' in a radial field
     • g=\(\frac{GM}{r^2}\)

3. Gravitational potential

   • Definition
     • 0PE level
   • Potential difference
   • Work done
     • \(\Delta\)W=m\(\Delta\)V
   • In a radial field
     • V=-\(\frac{GM}{r}\)
   • Graphs
     • g against r
     • V against r
   • V and g relationship
     • g=-\(\frac{\Delta V}{\Delta r }\)

4. Orbits of planets and satellites

   • Period and speed related to radius of orbit
   • Energy considerations
   • Geosynchronous orbit
     • Uses
     • Definition