Calculate the acceleration due to gravity

[Linco]

Many people mistakenly believe that austronauts that orbit the Earth are "above gravity." Calculate the acceleration due to gravity (g) for space shuttle territory, 200 kilometeres above the Earth's surface. Earth's mass is 6x1024 kilograms and its radius is 6.38 x 106 meters (6380 kilometers). Your answer is what percentage of 9.8m/s2?

Can anyone point me in the right direct to figure this out? I am not really sure what formula to use.

 

[OlderDan]

Which equation describes the force of gravity between any two point objects separated by some distance? The equation can also be used when the objects are both spherical, or when one of the two is very large and spherical.

 

[tony873004]

Your physics textbook probably gives the formula for acceleration. If not, it surely gives these two formulas:

$$F=\frac {GMm}{R^2}$$

and

$$F=ma$$

Use Algegra to combine these formulas to write an expression for $$a$$.
Hint: If you do it right, your little m's will cancel (illustrating that objects of different mass fall at the same rate ignoring air resistance).