Need help with potential energy question (1 Viewer)

[leesh95]

A satellite of mass 750kg is changed from an orbital radius of 7000 km to a geostationary orbit of 4.2*10^4 km. Calculate the change in its gravitational potential energy.

The answer is 3.7* 10^8 but I have no idea how to get this.Please help.

 

[ocstew]

The radius of geostationary orbit is found by using Kepler's Third Law and having a period of 24 hours. From there you can calculate the change in GPE by subbing the two radiuses into the GPE equation and subracting

 

[someth1ng]

Use the Ep=Gm1m2/d formula.

Change of Ep=Final Ep-Initial Ep

ie. Gm1m2 is the same for both but d is changed, in Final Ep, d=4.2x10^4km while Initial Ep=7000km