# Math Help - gravitational forces

1. ## gravitational forces

On earth, two parts of a space probe weigh 12000 N and 7900 N.

These parts are separated by a center-to-center distance of 22 m and
may be treated as uniform spherical objects.

Now, find the magnitude of the gravitational force that each part exerts on the other out in space, far from any other objects.

in Newtons

i know there is an equation for this:
and also one force will be in the positive directiona and the other in the negative.

need help.

http://www.mathhelpforum.com/math-he...s-problem.html

Have a look at that and see if it makes sense to you. Yes you're correct that the forces will be equal and opposite. There's one trick to this one. It gives you weight forces in Newtons. You'll need to convert those to mass before using the formula -

http://img508.imageshack.us/img508/1192/gravco8.jpg

3. dunno what happened, heres some answers:

for mass * 2 i get: 102.040816 grams

then for the radius i got 6.38 x 10^6 * 3 then squared which came to: 366339600000000

so then i used the formula and since there is only one mass, i only applied 1 mass?

and used gravitational force 6.67 x 10^-11

and came with 1.86 x 10^-23

which is not right, i think i did something wrong.