How does the gravitational force between two objects change with distance?

[elle]

Help, can someone please give me advice or hints on how to do this question.

http://tinypic.com/f44fnr.jpg"

I would provide working but I don't even know where to start

We are supposed to use this formula:

http://tinypic.com/f44kza.jpg"

 

[Tide]

You know what r is in both cases so just use the formula to express F and F' for both cases and compare the two results.

 

[elle]

I still don't understand...where does R come into the formula??

 

[Tide]

r is the distance between the center of the Earth and the object in question. That is the symbol people usually use but I just noticed the picture you showed uses "d" to represent that distance so r is the same as your d.

 

[elle]

Ok please bear with me if I sound dumb...never taken physics before so I'm finding it realli difficult
So do I have to find m1 and m2? And for G I've been given an approximation for it, and I don't know if I'm suppose to use it

 

[Tide]

Assuming that neither the mass of the plane nor of the Earth change then they both cancel out - along with G! They made it really convenient for you. :)