What is the mass of the second asteroid?

[thephysicslife]

Homework Statement

A 4.7x10^3 kg asteroid is acted on by a gravitational force of 2.0x10^2 N from another asteroid that is 3.0x10^2 km (3.0x10^5 m) away. What is the mass of the second asteroid?

Homework Equations

The equations we have been working with are

in which G is 6.67*10^{-11Nm^2/Kg^2}
and

But we don't have the information to use the second one

The Attempt at a Solution

in which I solved for m2

=

=5.74*10¹⁹ kg

The number is huge though which makes me think that I did something incorrect or used the wrong formula

 

[TSny]

Hello and welcome to PF!

Your work looks correct to me. The answer for the mass is large, but there are known asteroids with even larger masses.
See http://en.wikipedia.org/wiki/List_of_notable_asteroids#Largest_by_mass

 

[thephysicslife]

Thank you (for your help and the welcome) !
It seems like a very friendly forum so far :)