A Question on Newton's Laws

1. Oct 14, 2008

HodaM

I have got this word problem and I tried to solve but could not find the exact answer and I need the way to do it because my upcoming test has similar problems to it,,

1. The problem statement, all variables and given/known data
Saturnn has an equatorial radius of 6.00 * 107m and a mass of 5.67 * 1026Kg. Calculate the following:
a) the acceleration due to gravity of Saturn.
b) how many times greater is a person's weight on Saturn compared to that on Earth?

2. Relevant equations
F= mg
Fg= Gm1m2 / r2

3. The attempt at a solution
I don't know where to start from because I am used to solve similar problems starting with the acceleration due to gravity which is known to be 9.81m/s2, but this only applies for Earth gravity and I don't know how to start solving this problem

Thank you for any help

2. Oct 14, 2008

cristo

Staff Emeritus
Well, you can use your second equation to derive a g for Saturn, can't you?

3. Oct 14, 2008

HodaM

I guess so , the problem is that is joined the class late, and English is not my first language
but I will try my best

Thank you

4. Oct 14, 2008

cristo

Staff Emeritus
Sorry, my comment wasn't meant to come across as being abrupt. Perhaps I should rephrase it: how can you write your second equation so as to derive a 'g' for Saturn from it?

5. Oct 14, 2008

HodaM

Don't worry

I will try doing it and I understand it better now

Thank you very much