Satellite Orbiting Earth Energy

[blackheart]

1. A 962kg satellite orbits the Earth at a constant altitude of 99km. How much energy must be added to the system to move the satellite into a circular orbit with altitude 195km?

2. Homework Equations :

E = (-GMm)/2r
$$\Delta E$$ = E_f - E_i

3. My work (which produced the wrong answer)...

Ei = (-GM_Em_s)/(2(r_E + 99000m))

Ef = (-GM_Em_s)/(2r(_E + 195000m))

$$\Delta E$$ = ((-GM_Em_s)/2)((1/r_f)-(1/r_i)

The answer needs to be in MJ. I got 858MJ which is incorrect.

 

[Delphi51]

Hi blackheart. The method looks good. I got about half your answer.
Did you get 2.26 x 10^-9 for the difference between the 1/r terms?

 

[blackheart]

Oh! I didn't divide by two... I have it now. Thanks a bunch.

 

[Delphi51]

Most welcome.