Finding gravitational acceleration 3000 miles above Earth

[bengaltiger14]

I need to find the value of acceleration of gravity 3000 miles above the Earth's surface. I figured 3000 miles = 4.83 x 10^3 meters. Mass of the Earth equals 5.98 x 10^24kg. I used the equation:

g= GM/r^2 and get 17.1 m/s^2. This is too high a value. I don't think I am using the correct distance in my calculation. Any help Please?

 

[bengaltiger14]

Ok, I think I got is. I need to add the radius of the Earth which is 11.2 x 10^6 meters to the 3000 miles and the acceleration = 3.17 m/s^2 correct??

 

[BobG]

Ok, I think I got is. I need to add the radius of the Earth which is 11.2 x 10^6 meters to the 3000 miles and the acceleration = 3.17 m/s^2 correct??

Yes, it is correct (although I think you meant 3000 miles {4828 km} plus the radius of Earth {6378 km} equaled 11.2 x 10^6 meters.)