I actually know the answer to this one, you use pennies to find the atomic weight of a penny, it really doesn't have a weight. LOL
I think the answer is discovery.
Answer:
5.1 kg
Explanation:
Its mass on the moon is 5.1 kg because mass is an intrinsic property of a material and does not change with location. Although, its weight might vary because its acceleration of gravity g is dependent on the mass M and radius r of the planet(in this case, moon) involved g = GM/r². Since weight W = mg is dependent o g, weight varies but mass remains constant.