Review gravitational potential in Edexcel A-Level Physics through radial-field calculations, satellite energy changes and escape-velocity arguments.
Weather satellites may be in an equatorial orbit or a polar orbit, as shown.
A weather satellite in a polar orbit circles the Earth at a height of 8.50 × 10^5 m above the surface of the Earth.
Show that the gravitational potential at this height is about −5.5 × 10^7 J kg^-1.
mass of Earth = 5.98 × 10^24 kg
radius of Earth = 6360 km
Hence calculate the increase in gravitational potential energy when the satellite is placed in orbit.
satellite mass = 4990 kg
gravitational potential at the Earth’s surface = −6.27 × 10^7 J kg^-1
Increase in gravitational potential energy =