Weight of an Object on another Planet

[NkaujHelp]

Homework Statement

How much would a 1 kg mass weigh on the surface of a very dense planet with the same mass as Earth, but 1/2 Earth's radius?

Homework Equations

Eg(universe) = -G[(m1m2)/d^2]
Earth's Radius = 3,959 mi
Earth's mass = 5.97E24 kg

The Attempt at a Solution

If I plugged in those number into the universe gravitational energy equation along with the 1kg mass, will I get the answer in Newtons as the weight on that planet?
Because of the negative sign in front of that equation, the answer would be in negative? Is that possible?

 

[Orodruin]

You do not need to know the radius nor the mass of the Earth to solve this problem. Simply take the ratio of the weights.

The minus sign simply tells you the direction of the gravitational force, positive being away from the source.